Network TV shows—by design and in practice—are about the most innocuous entertainment in the world. There are so many levels of oversight to prevent anything offensive from making it onto the air. But once in a while, an offensive episode makes it to broadcast (or it becomes offensive in retrospect). And then it's not aired again for 20 years… or ever again.

1. Boy Meets World: the one where Cory and Topanga almost have sex.

They ultimately decided they weren't ready to risk having a spinoff.

Boy Meets World did okay when it aired on ABC in the early ‘90s, but it became a millennial touchstone because of endless reruns on the Disney Channel and ABC Family. One episode that never made it to the kid-centric cable networks was the fifth season prom episode, in which Cory and Shawn tried to get their dates to do what all teenage boys try to get their dates to do on prom night. (Sex. They wanted to have sex.)

2. Seinfeld: the one where Kramer burns a flag.

Who would ever associate Michael Richards with racism?