Whether it be a character twist, a plotline gone wrong, or a rushed ending. To put it in another way, what's that single writing choice that fatally wounded a promising show and turned it into a trainwreck?

For me, this is very easy:

The two-parter, May We Make Them Proud, from Little House on the Prairie. This completely ruined the wholesomeness of the show, ruined an entire set of characters, and set the entire series off track. Afterwards, it veered more and more into shock value and exploitation.

The two-parter of ER, when what's her face gets stabbed to death. The same thing happened, as with LHOTP. ER started out as this gripping medical show, then relied on shock value that only became more ridiculous with each year. The show was so desperate to keep things going that after exhausting every shocking death they could imagine, the writers then started writing these ridiculous scenarios (helicopters falling on people, ambulances exploding, wild wild west shootouts in the ER). :rolleyes:

Glenn's death on The Walking Dead killed it for me. Glenn was my favorite character and without him I just didn't see any point in watching. I know others felt differently but that's just the way I felt. His death was the death of the show for me.

On Desperate Housewives, the writers jumped like 5 years and made Eva Longoria fat or ugly. It totally wasn't needed. They later made her pretty again.

They should have had Dean Cain be a love interest for Teri Hatcher. However, it is said Teri was difficult to get along with.