Definitely agree with you; Harry narked me off so much, and I found JK's writing style immensely immature...
Plus, I hated how she killed off all of the character development for characters like Draco Malfoy just because she didn't like how people liked him better than they liked Harry.
Yeah, he was a bit troubled, but he had a busload of pride, which would not have let him act like he had.
I do, however, like that she got him to try and save one of his cronies (I forget which one. Bah!)