My go to reference for this is Search Party. The first season is the most engaging TV I've ever seen, the second season is still pretty damn good, but then the show got picked up by HBO and became total shit for 2 seasons. Like god I fucking hated season 4 of that show.
As far as movies go, I gotta go with Shrek the Third. 1,2 & 4 are all great, but what the fuck was 3?
I never finished Voltron: Legendary Defender. At first it was because I was too busy and distracted even if I liked the strong start it had, but when I returned, the "shipping" started to take over and I decided to read ahead to see if I wanted to take in the later seasons.
I did not like what I read. No spoilers, but it was both extra shippy and pissed off those very same shippers for some reason.