I won't say I hate any one kind of music in particular, because to branch all artists together and say you don't like them is pretty closed-minded. I have favourite artists, not favourite Genres.
In my oppinion, there is no "good" or "bad" music. Everyone just has different tastes.
And just because music is Mainstream doesn't automatically make it good or bad either. I have a friend who refuses to listen to Mainstream music because he desperately wants to be seen as being "unique" and "quirky".
I keep telling him, if he just opens himself up to everything and picks what he likes, he'll be more unique than any of these other folks who try to be different, but just wind up all doing the same damn thing.