I don't "hate" her, per se. Actually I get the impression she's pretty intelligent!
A) She knows how to put on a good "show" and attract the teeny boppers with nothing better to do (and no taste in music)... but it seems to me that's all it is, an act. I'm guessing in real life, she's as normal as anyone (just with a lot more money).
B) I caught her rant about whether or not she would participate in boycotting Arizona over our immigration law, to which she replied, "Do you really think anybody gives a _____ what us stupid F'n pop stars think?"
Now... as to her actual "music"... ehh... I guess there's no accounting for taste. Though I'd bet she'd be the first to admit that.