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?
Westworld Season 1 was very promising everything after was just Jonathan Nolan rehashing memento with robots and Jessie Pinkman with a toupee.
Mr Robot was a thrill ride but suffered from the boundaries of liberal thought as it tried to explain the outcome of its political choices and actions, leaning heavily on the surreal to fill in the gaps.