Sitcoms have been a part of television history since the very beginning, and the more successful series tend to stick around for a while. When this happens, a series that may have only planned for a few seasons can pull off several more if they're popular enough, and this can lead to interesting continuity details. Something that may have been a throwaway gag in one episode might come around five seasons later as a sort of reward for the fans that stuck with the series.
This has been common with newer shows than earlier sitcoms like The Flintstones, Family Matters, or The Cosby Show. Series like How I Met Your Mother and Community are famous for keeping the continuity gags going from one season to the next, and whenever someone spots something that's particularly interesting along these lines, they often take to the Continuity P*rn subreddit to share their findings. The best of what they've found regarding sitcoms are listed below.
A Funny Comment Made By Fry Came Back Around 46 Episodes LaterPhoto: Futurama / 20th Television
Redditor u/writeprompter potted one of Fry's girlfriends he referenced seasons before in a throwaway comment:
I'm going to jump on your top comment in hopes that maybe someone will actually see this. But in addition to this being continuity, it's also foreshadowing. Leela says that it was just a radiator, so how could it show up at Fry's funeral? Because it's all a fever dream inside Leela's coma.Cool detail?
A Single Line In An Episode Of 'The Simpsons' Paid Off Seven Seasons LaterPhoto: The Simpsons / Fox
The audience doesn't know a lot about Willie, but Redditor u/Harogaha noticed that a comment in one episode ends up paying off seven seasons later:
In The Simpsons episode "Monty Can't Buy Me Love," Groundskeeper Willie talks about how he was born, raised, and educated on a pool table, 7 seasons later Willie has a flashback and we can see the pool table he was born on.Cool detail?
The Simpsons Never Got Rid Of Their Giant HeadPhoto: The Simpsons / Fox
A gigantic head given to the Simpsons in the second season remains in their basement, and Redditor u/__variable__ noted just how long they've had it down there:
They've been keeping that for 26 years nowCool detail?
Beetlejuice Made An Appearance After His Name Was Spoken Three Times In 'Community'
A now-deleted Redditor found that the first three seasons of Community played out with a background joke:
Someone says "Beetlejuice" once in each of the first three seasons of Community. The third time, he shows up.Cool detail?