I find him annoying at times - the worse was when I first read O.O.T.P, I really wanted to yell at him!
It is slightly annoying how he goes off and does his own thing regardless - like in P.O.A, going off to honeydukes when he knows full well a murderer is after him and people are worried for his safety.

I kind of understand when people say how he's just a kid, he's stil growing up, finding himself etc, but at the same time it is hard for me to see Harry's point of view since I was more like Hermione at school with the whole, not breaking rules thing! *lol*