Oh, I dunno. I could easily imagine Daniel Radcliffe screaming and shouting and pouting the way Harry did in the novels. He has a tendency to bellow the Patronus spell (I thought that required thinking of something that makes you happy... those aren't happy-sounding shouts).I stopped watching after the third one IIRC. Whenever one of them has caught me unawares on TV while channel-surfing I've always been struck badly enough by the characterisation to stick around for more than half a minute.
Don't knock the movies. They're what got me into the fanfiction and videos, which in turn prompted me to read the novels. Yes, I realize I'm doing this backwards, but at least I got here.