Time travel is tricky. Not because science hasn't figured out how to make it a real thing, but because anytime it's used as a storytelling device, the plot can be compromised by the type of mind-bending paradoxes that can ruin suspension of disbelief. Rian Johnson's latest film Looper, out Friday, is a time-travel flick that sidesteps most of the problems presented by time-travel tropes. By focusing on a smart, character-driven story instead of getting bogged down in the "what if?" questions, Johnson's film stays above the fray. "Time travel is a really weird thing in narratives because it's so easy for it to completely take over the narrative and suddenly all you're thinking about is butterflies and paradoxes," Johnson told Wired at Comic-Con International. Looper even manages to poke a little fun at time travel. During one scene where a young man named Joe (played by Joseph Gordon-Levitt) is talking to his future self (Bruce Willis) in a diner, the elder Joe finally says, "I don't want to start talking about time travel because if we start talking about time travel, we're going to be here all day, making diagrams with straws." (Spoiler alert: Minor plot points follow.) That doesn't mean the film is totally without time-travel tropes. Without giving too much away, Looper serves up a pretty strong twist on the idea of going back in time and correcting what once went wrong – a concept that's popped up in flicks as disparate as Timecop and Hot Tub Time Machine. More specifically, Looper has a weird twist on the Hitler murder paradox, which essentially points out that there are a slew of pitfalls in going back in time and killing somebody. In honor of Looper's smart storytelling, Wired is taking a trip back in time to revisit some the best time-travel flicks of the past. Click through the gallery above for a guided tour of some of the finest space-time-shifting tropes on film. [h/t to the TV Tropes wiki for incredible insight] Photo: Alan Markfield/Sony Pictures

Standard Temporal Paradoxes Temporal paradoxes exist in almost every time-travel story. They have to: Because of complications arising from the butterfly effect, it's nearly impossible for a person to go back in time and not change something, no matter how small it seems. Pondering how your every action would affect things in a multiverse timeline can drive you nuts. Remember in The Terminator when Sarah Connor told Kyle Reese, "You're talking about things I haven't done yet in the past tense; it's driving me crazy"? It's like that. And it's like that moment after she said that where you immediately thought, "Wait, would she have raised a badass like John Connor if she hadn't spent this formative time fighting off a machine?" This is (kind of) explained at the end of Terminator because ... (see next slide.)

The Past You're in Has Already Been Altered by the Future In Sarah Connor's case, it turned out that the son she would have and raise was already the product of Reese – having been given a picture by John Connor of his mother and sent back in time to knock up John's mom (wait, what?) – and his involvement in her life. Reese wasn't going back to fix anything, just enacting what was meant to happen. This also comes up in 12 Monkeys when James Cole (played by Bruce Willis) realizes again and again that no matter how many times he gets sent back in time, he can't effectively stop the viral outbreak that kills millions of people. Or, as he tells the panel at the mental hospital, "How can I save you? This already happened."

Going Back to Set Right What Once Went Wrong Some element of this trope comes up in almost any instance where time travel is used as a narrative tool – including in Looper. But really, if time travel were real, the ability to fix what once went wrong would be a highly alluring proposition. Hence it's a concept that comes up in everything from the TV show Quantum Leap to Star Trek: First Contact to the Jean-Claude Van Damme vehicle Timecop (above).

You Got a Phone Booth? Well We Got a Freakin' DeLorean! In Looper, the audience hardly ever sees the time machine, and little is divulged about how the invention works. But in previous time-travel offerings there has been a heavy emphasis on the mechanics by which the traveling through time happened. From TARDISes to DeLoreans to Bill and Ted's phone booth, cinemas have been the battlegrounds where filmmakers have tried to put on-screen the coolest gadget ever for making the journey through the eons. (I think we can all agree that battle was finally won with the creation of the Hot Tub Time Machine.)

It's Funny 'Cause We Know Where This Is Going One thing that's hard to pull off but great when it works is the history buff in-joke. Hot Tub Time Machine was full of such quips – things that are probably only funny to real '80s babies. One of the best, yet maybe most obvious, examples of this type of historical joke is the moment when Marty McFly "invents" Chuck Berry's sound by playing "Johnny B. Goode" at the school dance.

It's Funny 'Cause We Know Where This Is Going One thing that's hard to pull off but great when it works is the history buff in-joke. Hot Tub Time Machine was full of such quips – things that are probably only funny to real '80s babies. One of the best, yet maybe most obvious, examples of this type of historical joke is the moment when Marty McFly "invents" Chuck Berry's sound by playing "Johnny B. Goode" at the school dance.

You're From the Future, Huh? Prove It! If you tell someone you're from the future, they're going to call your bluff or find some way to make you prove you know something that hasn't yet happened. Remember that moment in 12 Monkeys where Madeleine Stowe figures out Bruce Willis might've actually been from the future because he knew that kid was faking being trapped in a well? Yeah, it's like that. In a more recent example from Sound of My Voice, the young followers of cult leader Maggie (played by Brit Marling, standing above) ask her to sing a song from the future. She opts to belt out "Dreams" by The Cranberries. Some take this as a sign she's a fake, while others give her the benefit of the doubt that a time traveler from 2054 could've not known the Cranberries existed and thought a cover version was an original. Photo courtesy Fox Searchlight