Well, somebody already posted my choice which would be episodes 7, 8, and 9, so I’m going with the next thing that popped into my head and ignore part of the question and that this is a movies sub.

With that said, my answer is How I Met Your Mother, because it still angers and disappoints me years after watching the show. Fuck you writers, it’s not all about Robin. Such a legend - wait for it - dary show ruined right at the end.