Twenty-five years ago—on September 22, 1994—Friends made its NBC debut and forever changed the face of American sitcoms. In addition to turning its six stars—Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc, Matthew Perry, and David Schwimmer—into household names (and eventually some of the highest-paid actors in television history), the series actually helped to get Mental Floss off the ground (more on that later). Here's a look back at the series that is still one of the most streamed shows in Netflix's library.

1. Friends was originally called Insomnia Café (and a bunch of other things).

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In the early 1990s, Friends co-creators David Crane and Marta Kauffman wrote a seven-page pitch for a new sitcom titled Insomnia Café. In addition to the different title, the plot itself was quite different from what came to be known as Friends. For example, Ross and Rachel weren't the key relationship; instead, Joey and Monica were supposed to be love interests.

After NBC bought the pilot, the title became Friends Like Us. NBC president Warren Littlefield came up with another title that was also considered, Across the Hall. By the time they shot it, the title had switched again to Six of One. When the show premiered on September 22, 1994, they had finally landed on simply Friends.

2. The cast could have been completely different.

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With a cast of six people, it’s not a surprise that many different actors were considered for each role. For example, Kathy Griffin and Jane Lynch actually became friends after meeting while both were auditioning for the part of Phoebe.

Both Jon Favreau and Jon Cryer were considered for the role of Chandler before it went to Matthew Perry, but Perry almost didn’t get the gig either. During the 1994 pilot season, he filmed the pilot for a show called LAX 2194 in addition to Friends. The show would have been about baggage handlers at LAX who sorted aliens’ luggage. Thankfully, it wasn’t picked up, and Perry was able to take the Friends gig.

3. The producers wanted Courteney Cox to play Rachel, but cox resisted.

Before the show premiered, Courteney Cox was probably the most famous cast member. She was known for many commercials plus Bruce Springsteen’s “Dancing in the Dark” music video. The Friends producers originally asked her to play Rachel, but she requested the role of Monica because she liked the “strong” character.

4. The role of Ross Geller was written for David Schwimmer.

This may come as a surprise because Eric McCormack (best known as Will of Will & Grace) made news when he said that he auditioned “two or three times” for Ross. But, executive producer Kevin Bright had worked with Schwimmer before, so the writers were already developing Ross’s character in Schwimmer’s voice. And indeed, Schwimmer was the first person cast on the show.

5. The opening credits were not shot in New York.

Don’t let your New York City tour guide trick you into thinking that you’re looking at the fountain from the iconic opening credits of Friends—unless you’ve brought your tour guide with you to Burbank for some reason. Although the fountain looks a lot like Central Park's Pulitzer Fountain, the actual shoot occurred on a Warner Bros. lot.

6. The cast took a trip to Las Vegas together before the show aired.

Director James Burrows, who went on to direct a handful of episodes for the show between 1995 and 1997, brought the six cast members to Vegas because he “had a feeling about the show.” While they were at Caesar’s Palace, he encouraged the group to enjoy themselves. “This is your last shot at anonymity,” Burrows told them. “Once the show comes on the air, you guys will never be able to go anywhere without being hounded.”

7. Caesar's Palace played an important role on Friends later on.

Caesar's Palace played a key role in the fictional world of Friends as well. In "The One in Vegas," the season 5 finale, Joey is seen playing a gladiator at the Vegas hotel. This is, of course, the same episode where Ross and Rachel get married in a drunk stupor and come stumbling out of a Vegas chapel while Monica and Chandler, who were about to get married, look on.

8. Monica was an early Mental Floss fan.

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In the 2003 episode "The One With the Soap Opera Party," Monica is shown casually reading a new magazine called Mental Floss while hanging out at Central Perk. We really owe David Arquette a lifetime of gratitude because he's the one who made it happen. "I thought it was so interesting," Arquette told Entertainment Weekly at the time, "[so] I gave it to Courteney" for the show.

9. Lisa Kudrow didn't know how to play guitar.

"I didn’t like the guitar," Lisa Kudrow admitted about Phoebe Buffay's chosen musical instrument. "I wasn’t getting it. So I think I even asked, ‘What if she plays the bongos?'" They ended up bringing a guitar teacher in, but that didn’t last long. Kudrow learned a couple of chords, then announced that she was done with the lessons. She decided that Phoebe would only know a handful of chords anyway. And thank goodness because “Smelly Cat” is perfect just the way it is.

10. Friends was filmed in front of a live audience—except for cliffhangers.

Shooting an episode of Friends was a lengthy process, typically lasting five hours, with multiple takes per scene and 20 minutes between scenes to change sets. Still, the show was filmed in front of a live audience made up of 300 fans. And that’s the way the cast preferred it. “It’s kind of like a test to see if the material works, if the jokes work, if the story tracks,” LeBlanc said. Perry agreed, “Our energy just elevates every time there’s an audience.”

So, what wasn’t filmed in front of a live audience? One example is the cliffhanger in the season four finale, “The One With Ross’s Wedding.” At the end of the episode, Ross is about to marry Emily, but accidentally says Rachel’s name at the altar. “We couldn’t have an audience for that,” Aniston said. “We always remove the audience for the cliffhangers because, obvious reasons, you don’t want to spoil it.”

11. Many people, including Lisa Kudrow, thought that Chandler was gay.

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Kudrow said that she was surprised to hear Perry’s interpretation of Chandler at the first table read because when she first read the script, she thought Chandler was supposed to be gay. And she wasn’t the only one. During the first few seasons of the show, many fans speculated about Chandler’s sexual orientation. In 1997, David Crane told Entertainment Weekly, “No, Chandler isn’t gay. Nor will he be gay.”

12. They were the first TV cast to negotiate as a group.

During the first season, each cast member was receiving around $22,000 per episode. But allegedly, by the second season, each actor had a slightly different salary. In 1997, all six cast members refused to work until they all earned an equal salary of $100,000 per episode. This was big news. “Stars of hit shows often threaten to boycott their series in pursuit of higher salaries," The New York Times reported. "What is unusual is this cast’s effort to use solidarity as leverage."

This negotiation worked very well. By the final season, each cast member was earning $1 million per episode.

13. Phoebe Buffay’s twin sister, Ursula, was also a character on Mad About You.

Kudrow was already playing Ursula the waitress on Mad About You when she was cast on Friends. NBC and Mad About You encouraged Kudrow to take both roles. According to her, it was the producers of Friends who decided to “address this and say they're twin sisters.” She went on to play Ursula Buffay in eight episodes of Friends as well.

14. The apartment numbers switched during the series.

At the beginning of the series, Monica’s door had the number 5 on it. The producers later realized that didn’t make sense as Monica lived on a higher floor. They changed her apartment number to 20. The number on Chandler’s apartment changed as well—from 4 to 19.

15. There was a connection between Friends and Home Alone.

In 2016, the folks at 22 Vision realized a sort of bizarre connection between Friends and Home Alone: The house that Monica and Chandler bought at the end of the series looked an awful lot like the house owned by the McCallisters in Home Alone. Check out the video above and you'll notice that the view of the neighborhood from inside Monica and Chandler's house reveals the same exact one seen from inside the McCallister residence in Home Alone, right down to the blue garage of the Murphys' house across the street.

In 2016, the folks at 22 Vision shared a video documenting a previously unrealized connection between Friends and 1990's Home Alone. It turns out that Monica and Chandler may have bought the house owned by the McCallisters in the movie. How is that possible? With the help of some Hollywood trickery.

16. Kudrow’s pregnancy was written into the show, but Cox’s was not.

Kudrow got pregnant with her son, Julian Murray, in 1997. Kudrow was dubious about Phoebe getting pregnant, too, but the writers decided to have Phoebe act as a surrogate for her brother’s triplets. On the other hand, in the final season, Cox was pregnant with her daughter, Coco Arquette. This was not written into the show for an obvious reason: the series had already established that Chandler and Monica couldn’t have kids. So, they hid Cox’s pregnancy to the best of their abilities with costumes and props.

17. Joey’s Magna Doodle art became a job for the crew.

Over the years, a few crew members were responsible for drawing on the Magna Doodle on Joey’s door. But in the later seasons, it was primarily a job for Paul Swain, who was the best boy on the electric crew.

The Magna Doodle became one of the show’s stars. It sat right in the middle of Joey’s door, so whenever a character walked through that door, the Magna Doodle was prominently displayed. Fans became obsessed with the drawings. Swain said, “They were looking for hidden meanings being given through the Magna Doodle.”

18. Matt LeBlanc took the Magna Doodle.

Unsurprisingly, LeBlanc had a soft spot for the Magna Doodle, too—and actually took it with him when the series ended. (He took the foosball table, too.) It even found a second life on his short-lived Friends spinoff, Joey.

19. The actors didn’t always play well with animals.

It was widely publicized that Kudrow was afraid of the duck who made an appearance in season three. Before that, Ross had a pet monkey, Marcel, who was actually played by two monkeys: Monkey and Katie. Marcel was written out of the show in season two because it became too time-consuming to shoot scenes with a monkey. According to Katie’s trainer, Nerissa Politzer, Monkey was once supposed to pick up a bra, but ended up throwing it at Aniston instead. There’s a fun blooper (at about the 6:20 mark above) in which Rachel is trying to explain a TV show to Marcel, but it doesn’t go so well.

20. The cast had a huddle before every episode.

Every week before filming commenced, the cast would get together for a moment to prepare for the show. This was the moment that Schwimmer was dreading before the finale because he knew it would make him emotional. “I started to lose it in this ritual that we had before the show," he said, "which is just a group hug, kind of get in a little circle, right before we come out. And that was the moment I was dreading for a long time because I knew that moment of just looking at everyone in their eyes, and saying ‘Have a good show,’ and knowing that was the last time we were going to be able to be in our little circle.”

21. For the opening credits in “The One After Vegas,” everyone was given the last name “Arquette.”

This episode was the sixth season premiere. It was also the first episode after Courteney Cox married David Arquette. In the credits, her name was switched to “Courteney Cox Arquette” and the other cast members followed suit with new names like “Jennifer Aniston Arquette,” “Lisa Kudrow Arquette,” and so on. You can see the credits above. The episode is dedicated: “For Courteney and David, who did get married.” (The couple divorced in 2013.)

22. Cox and Matthew Perry confronted Judd Nelson on a nearby soundstage about an on-set bet.

While promoting the show on The Tonight Show with Jay Leno, Cox told the story of an elaborate bet between her and Perry that later involved the major '80s star.

“One day I was on the set, and I was sitting around, reciting this line, like, doing this imitation of Anthony Michael Hall,” she told Leno. “He has this line in a movie. The line is, ‘Chicks cannot hold their smoke, that’s what it is.’ And Matthew Perry walks over to me and very adamantly says, ‘Oh, Weird Science.’ And I said, ‘No, Matthew, that’s The Breakfast Club.’ And he was 100 percent sure that it was Weird Science and I was 100 percent sure it was The Breakfast Club.”

More and more crew members got involved in the debate and the stakes kept rising. “We realized that Judd Nelson was over on stage 29, doing Suddenly Susan,” said Cox. “So, we ran over there and found out that yes, indeed, it was The Breakfast Club.” As for the bet, once Cox finishes telling her story to Leno, she rings a bell and Perry brings her a tissue. She tells Leno that Perry has five more months of being her “man slave.”

23. For “The One with the Dollhouse,” the props department had to make SIX different cardboard dollhouses.

In the season three episode, Phoebe makes a dollhouse out of cardboard. But the dollhouse ends up catching on fire, which meant six identical ones had to be created from scratch. And in true television deadline fashion, they were put together in three days. The Friends props master, Marjorie Coster, described it as the “pièce de résistance” of the department.

24. In “The One Where Old Yeller Dies,” a few takes were messed up thanks to a chatty kid.

The plot of the episode is that Rachel hears the first word of Ross’s son, Ben. Ross is desperate to hear Ben talk again and spends the rest of the episode trying to get his son to talk. In one scene, Ross says, “It’s Ben and his Dada. Dada. Can you say ‘Dada’?” He’s supposed to be met with silence, but the child actor kept actually responding, “Dada.” Later in the series, Ben was played by Cole Sprouse, who would go on to star with his twin brother in the Disney Channel show The Suite Life with Zack & Cody.

In 2001, two of these bloopers were released on Late Night With Conan O’Brien. You can see them here (at 9:30).

25. Matthew Perry struggled with addiction during production.

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In 1997, Perry went to rehab for an addiction to prescription drugs and alcohol. He went again in 2001. He later told People, “I was never high at work. I was painfully hung over. Then eventually things got so bad I couldn’t hide it and everybody knew.”

26. Matt LeBlanc spent several years hiding from his Friends fame.

In a 2016 interview with The Mirror, LeBlanc talked about the dark side of fame. "For years and years, I barely left the house. I was burnt out," LeBlanc said. "I wanted to not have a schedule, not be somewhere. I was in a position to do that. My agent was bummed. Most actors call their agents and say, 'What’s going on?'. I’d call mine and say, 'Please lose my number for a few years.' It was a very dark time. I almost had a nervous breakdown."

27. David Schwimmer had trouble dealing with his immediate fame, too.

LeBlanc wasn't the only cast member to struggle with the newfound fame that Friends brought to the cast. "It was pretty jarring and it messed with my relationship to other people in a way that took years, I think, for me to adjust to and become comfortable with," Schwimmer said during an appearance on The Hollywood Reporter's "Awards Chatter" podcast.

28. Jennifer Aniston almost didn’t return for the last season.

By the time the show ended, Aniston was arguably the most famous cast member thanks to films like The Good Girl and Bruce Almighty. Her then-husband, Brad Pitt, didn’t hurt her celebrity status either. With that fame came the rumors that she was almost responsible for the show ending prematurely. In a 2004 interview, Aniston admitted that she had hesitations. “I had a couple issues that I was dealing with,” she said. “I wanted it to end when people still loved us and we were on a high. And then I was also feeling like, ‘How much more of Rachel do I have in me?’” She eventually agreed to the final season.

29. There are Central Perk cafes based on the famous coffeehouse from the show.

While there isn’t an actual Central Perk in New York City, the fictional cafe has inspired some real ones. In 2010, Friends fan Du Xin opened a Central Perk replica in downtown Beijing, which became extremely popular. Its success meant that Du Xin could later afford to reproduce Joey’s apartment next door. In 2012, another Central Perk popped up in Liverpool.

30. Bruce Willis appeared on the show for free after losing a bet to Perry.

Apparently Perry was quite the gambler. He got into a debate with Willis while the two were making The Whole Nine Yards. Perry believed that the film would be number one in the box office on its opening weekend, but Willis disagreed. In February 2000, the film was number one. Willis was set to appear on Friends as the dad of Ross’s girlfriend and Rachel’s love interest. As a result of the bet, he had to donate his earnings for the guest stint to charity.

31. It featured a lot of future stars.

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In addition to making household names of its main cast members, Friends gave an early start to several soon-to-be stars as well. Among the now-familiar faces you might see if you rewatch the series, including Grey's Anatomy star Ellen Pompeo, Melora Hardin and Craig Robinson from The Office, and Riverdale's Cole Sprouse.

32. Fans have concocted a lot of bizarre theories about the show.

Did the entirety of Friends take place in Rachel's dream? Or in Phoebe's hallucinatory mind? Over the years, fans of the show have come up with a host of theories to explain particular aspects of the show—and some of them are pretty bizarre.

33. James Michael Tyler was working as a barista when he was cast as Gunther.

In 2014, James Michael Tyler—the actor who played Central Perk's Gunther—told BuzzFeed that he was working as a barista in real life when he was cast on the show. "I had a job at a coffee shop called The Bourgeois Pig in Hollywood, which is still around and one of the last independent coffee shops that hasn't been taken over or whatnot. I was one of their first baristas—I think I started there in 1990 or so."

34. Gunther's bleached hair was accidental.

"I had a friend who wanted to be a hairdresser and wanted to practice bleaching someone's hair, so I offered what hair I had left at the time," Tyler told BuzzFeed. "It came out white and that was the night before I was called in for the first day of shooting the first season." As he was originally hired as a background actor, just to give the Central Perk set some authenticity, it didn't seem like a big deal ... until his role became a recurring one.

"I bleached my hair every week for 10 years," Tyler said. "I did it myself after a while. It was just easier instead of coming in early to do it. I would just do it the night before."

35. It's one of the most watched shows on Netflix.

The Holiday Armadillo has granted your wish: “Friends” will still be there for you in the US throughout 2019 pic.twitter.com/Yd0VqRzk3r — Netflix US (@netflix) December 3, 2018

Decades after its premiere, Friends still maintains a massive fan base. In the UK, it's the most streamed series on Netflix, and it holds the number 2 spot in America (only The Office gets more viewers). In late 2018, when Netflix announced that the series would be leaving the service on January 1, 2019, fans revolted; a Change.org petition to bring the show back was launched and #Justice4Friends became a trending password. Amazingly, it worked!

36. British fans love Ross Geller.

In a 2016 survey by Comedy Central, Friends fans in England were asked to vote for their favorite cast member. Schwimmer's Ross Geller came out on top with 25.6 percent of the vote, just edging out Chandler Bing, who 25.4 percent named as their favorite Friend.

37. None of the actors was a huge fan of the theme song.

Though it's impossible to imagine Friends without also envisioning the opening credits, in which the cast play in a fountain and dance along to the Rembrandts' "I'll Be There for You," apparently no one was a huge fan of the tune. "No one was really a big fan of that theme song,” Aniston said while appearing on The One in 2016. She then backtracked a bit: "I don't mean to say that. We felt it was a little, I don't know. Dancing in a fountain felt sort of odd, but we did it."

38. Aniston probably watches the show as much as you do.

While there are a lot of actors who can't bear to watch any of their projects, Aniston isn't one of them—at least not when it comes to Friends. While appearing on The One, Aniston said that she can't resist leaving the show on when it comes on TV. "I can't help it," she said. "First of all, I'm trying to remember which episode it is. Then, half of the time I'm saying to myself, 'I don't remember that!’ It's just that you can get sucked in to the nostalgia of it.”

39. The identity of "Ugly Naked Guy" wasn't revealed until 2016.

A dozen years after the series finale of Friends aired, intrepid HuffPost reporter Todd Van Luling finally uncovered the identity of the man who played "Ugly Naked Guy" on the show. The character—who lived in the apartment across from Monica and Rachel—was frequently referenced, but only ever appeared on the show twice. And in neither of those appearances was his face visible. But after a year of research, Van Luling finally had his answer: Ugly Naked Guy was an extra named Jon Haugen. (Though Van Luling's account of how he tracked this information down is worth a read.)

40. A (real) reunion isn’t happening.

In 2015, Cox went on the Late Show with David Letterman where he asked her about the possibility of a reunion. Cox responded, “It’s not going to happen.” She went on to explain that it’s difficult enough for the six of them to get together for a cast dinner, let alone a full-fledged reunion.

Kauffman and Crane have similar views about a reunion. In a 2014 interview with Entertainment Weekly, Crane said, “People say they want it, and the more that we say it’s a bad idea, people [disagree]. But I think if we actually gave it to people, there would be such backlash.”

A Jimmy Kimmel segment from 2014, which you can watch above, may be as close as we're going to get.

This story has been updated for 2019.