The Good Wife - CBS
Archie Panjabi and Juliana Margulies allegedly hated each other so much that their final scene together was put together via editing so that they didn't need to be in the same room as each other. The scene in question was clearly altered.
Two and a Half Men - CBS
Charlie Sheen went off the deep end, trashing the creator of the show at every opportunity. He was swiftly fired, and the show was never the same again. Not even Ashton Kutcher could save it.
Martin - Fox
Tisha Campbell filed a sexual assault lawsuit against her co-star, Martin Lawrence. It meant the two could no longer film scenes together. The whole basis of the show was on their characters being love interests, so the show was later canceled as ratings slipped.
Bull - CBS
Viewers were stunned when it emerged that Eliza Dushku had turned to CBS about sexual harassment at the hands of Bull's leading man Michael Weatherly. Even more shocking was that the only reason the news came out was a result of an investigation into disgraced CBS former CBS CEO Les Moonves.
Beverly Hills, 90210 - Fox
Jennie Garth and Shannen Doherty HATED each other. They argued on the set of the series, and Tori Spelling later revealed that the set had become so toxic that she asked her father, Aaron Spelling, to oust Doherty from the series. It was never the same.
Charmed - The WB
Are you sensing a pattern with Shannen Doherty here? Shannen left Charmed early into its run after bickering with co-star Alyssa Milano. While Doherty's exit has never really been addressed away from the show, there's this huge rumor that Doherty did not leave of her own accord.