Gather round, kids, and listen to your old man tell you a tale. Back in the olden days, we didn’t have unlimited MetroCards. If you wanted to ride the subway, you had to pay individually for each ride. Every time we wanted to go somewhere, we’d have to pony up our hard-earned quarters. No one ever took the L train at rush hour just for fun like they do today.

Then, one day, an ambitious NYC transit employee named Joe got an idea. Maybe there were people who’d take the subway more if they didn’t have to pay for each ride individually. Maybe there could be a different way to buy subway rides — a better type of MetroCard. An unlimited MetroCard. And maybe Joe could be the one to finally putting that connecting worm inside The Big Apple.

So Joe waited and waited until the time was right, and then he called a meeting to pitch this plan to his boss. He was nervous — back in those days, people didn’t just make changes to the subways like they do today. His boss scoffed at first. “But Joe, people will just swipe their friends in. No one will pay for their own rides. It’ll be like Netflix, which will be invented in 100 years.”

“No,” said Joe, “we’ll make them wait. Once they swipe their unlimited MetroCard, they won’t be able to use it again right away”

“But how long will they wait?” Said his boss.

“15 minutes,” said Joe confidently.

“No,” said his boss, “15 minutes is too short. Two old friends might be willing to stay and chat in the station for that long while they wait to swipe the next one in.”

“Fine,” said Joe. His boss’ rejection was a temporary setback, but he believed he could get past it. If only he had another idea. Then it dawned on him. “Let’s do 21 minutes,” Joe said.

“21 minutes! Are you crazy?” Asked his boss, “What if someone takes the 6 from 77th and Lex to 96th and Lex, and then wants to get on the 96th street crosstown? They’ll have to wait 3 minutes to swipe their card again, the 6 is so fast!” (please remember that this was the good old days).

Joe saw his boss’ point, and he knew he needed another idea. “16 minutes! A 16 minute waiting period!” He said.

“That’ll never work, Joe,” said his boss, “people will just swipe their cards, play ‘Hey Jude’ twice, and then sell off their next ride. The MTA will go bankrupt by June.”

At this point, news of Joe’s crazy idea had traveled throughout the city (very expensively, of course, owing to the lack of unlimited public transit). Many of Joe’s colleagues had gathered to witness for themselves the pitch meeting that would change history. The woman Joe had secretly loved for years, stood in the back of the room. Joe wasn’t about to let them see him fail, so he took another stab. “A 20 minute waiting period. 20 minutes is perfect,” he said to his boss.

“20 minutes! We can’t do that,” announced his boss. “What if someone takes the 6 from 77th and Lex to 96th and Lex, and then wants to get on the 96th street crosstown? They’ll have to wait 2 minutes to swipe their card again, the 6 is so fast!”

Foiled again! Joe didn’t know what else to do, but he knew he had to keep trying. He’d come so far. “Ok,” said Joe, taking a deep breath, “17 minutes?”

“17 minutes! That’s insane!” his boss scoffed. “17 minutes! Someone could swipe their card, listen to 17 minutes of a podcast, then sell the next swipe to a hobo!”

“What’s a podcast? Who listens to them?” asked Joe.

“No one knows,” replied his boss, “but just know 17 minutes is too short. They’ll have barely gotten past the advertisements.”

“Fair enough,” said Joe, who didn’t really believe it was fair. Now he was close to giving up. It didn’t seem like any amount of time would be right for unlimited MetroCards. Still, while he had the attention of the whole MTA, he decided to put his career on the line and try again. “Then what about 19 minutes?” Joe asked.

“19 minutes!” his boss cried, “What if someone takes the 6 from 77th and Lex to 96th and Lex, and then wants to get on the 96th street crosstown -

“Ok, I get it! You said that already!” Joe yelled. He was ready to give up. He’d tried everything he could to sell his boss on unlimited MetroCards. It was hopeless. All his hard work for nothing. Unless — maybe there was something he was forgetting. His boss was about to leave the room when an idea popped into Joe’s head.

“18 minutes!” Joe shouted, “We’ll make them wait 18 minutes between rides!”

His boss turned around slowly, his face full of shock. The rest of the transit workers stood still. Sally beamed at Joe; he blushed. He’d finally done it. “Gosh darn it, Joe, you’re a genius! 18 minutes is the perfect amount of time! We’ll start selling unlimited MetroCards immediately! Wherever did you get that brilliant idea?!” His boss exclaimed.

And they did. And that, kids, is the story of why the wait time for unlimited MetroCards became 18 minutes. Now can someone swipe me in?