Rick and Morty is a prime example of things that have been destroyed by its own fans. Arrow (Olicity...) or Undertale is also a really good example.
R&m though really is a victim of its fanbase. I tried watching the fan favorite s3e01 with my dad, who has seen all of seasons 1 and 2, and he really couldnt follow the plot. It made me realize that I probably only liked it because I watched each episode of seasons 1 and 2 at least twice (the dvd commentary is great). I'm just going to skip watching the council of ricks episode from season 3 with him, it's really self indulgent.