I own all the movies and I hate myself for it. I've never really tried to define what it is about them that irritates me...I guess it's that he's a wuss. I just can't like him. He doesn't seem to have grown that much in 5 movies...still incompetent, insecure and whiny. And I also think Rowling has gotten a ton of undue credit for originality. There isn't anything in there that I haven't seen before (though I'm pretty nerdy).
But the latin thing..."reducto!"...ugh.
I love Robbie Coltrane and Richard Harris (very sad to lose him) and I don't mind their roles, but I find the movie slightly demeaning to the likes of Oldman, Fiennes, and Rickman.
It may all be Radcliffe's fault though, but I won't know until I see him do something else. Ha.