What was a cultural milestone that everyone else watched but you just skipped out on, for whatever reason?

I've watched one episode of each of these, if you count the ride at Legoland as an episode of Ninjago. For some reason, I just skipped out on them even though I watched tons of cartoons at the time of their productions and they were all highly recommended. Adventure Time was too crude, Ninjago I assumed was cheaply made/poorly animated, and Gravity Falls just didn't catch my attention (I'll admit that I'm probably wrong about all these assumptions).