every once in a while, a character comes along who is simply so odious that even a sympathetic back story can't keep me from hating them. this phenomenon could theoretically be called the Abby Morgan problem, but even Abby Morgan (Dawson's Creek) had a few minor redeeming qualities.
for those of you who don't seek out old TV shows from the 80's and 90's, Emily Valentine was a recurring character in the early seasons of 90210. she was troubled and had spiky platinum hair and Brandon like, felt a crazy love connection to her until she took him to a club and forcibly drugged him with something ecstasy-ish called U4EA. then, after he ends it because of said drugging she goes even more batshit insane and starts stalking Brandon and gets paint on his favorite shirt and threatens to kill herself and him and ruins the gang's spirit float and eventually lights a big fire. although they give her a resolution in the next season where she's clean and going to Scotland to study whales - i still hate sober Emily Valentine just as much.
and sure, a character like that can make for some good TV...and maybe i just really have something against that actress (this post was inspired by her playing an equally crazy and insufferable character named Quincy of all things on an episode of 21 Jump Street). but what The Emily Valentine Problem boils down to is this: if a character is so fucking awful/obnoxious/sociopathic as to turn the viewer off, it becomes clear that the writers are simply forcing this character into the situation to create drama and the reactions of the other characters start to ring false. in real life, people wouldn't put up with Emily Valentine; they would call the police, lock her out and tell her she's a crazy bitch. however, The Emily Valentine Problem can be resolved using one of several tried-and-true methods.