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?
Bones
The first 3-4 seasons are really good. Lots of sets, lots of live action, lots of really good practical effects, and based pretty well in real(ish) science. Season 1 in particular has a ton of Bones beating people up which i personally love and wish theyd kept throughout the series. It's a Bush era show aired on Fox, so there's cop worship and "gotta defend the homeland" brainworms, but I like that the message universally is that the cops are too dumb to solve crimes and they need the smart people in a lab to figure it out for them.
Show drops off immensely after season 4. The stakes feel lower, the writing isn't as witty, they got a toyota sponsorship so once an episode a character will all but straight up look in the camera and say "but a toyota you pathetic worm". Less on location shots, more CGI. Just disappointing after seeing what they could do. It was probably the only network TV crime drama I liked.