And it's not just Harry who's time and again out of his depth; the supporting characters can be rather useless, too. Not surprisingly, I love OotP so much: it shows that the designated good guys are really a bunch of screw-ups and that the fate of the wizarding world lies in the hands of a sulky and shouty teenage boy. In fact, OotP was when I started to like Harry; I had been rather indifferent to him prior to that.

the choices he made, not because some special gift he was born with

Not to mention the choice that Voldemort made for him when he marked him!