As far as we know, Harry's dad was only a jerk as a boy, and mostly only towards Snape. We have testimony elsewhere that he was a pretty good fellow, after he matured a little. Of course, it's assumed that part of that was the love of a good woman.

But as far as we know, Harry's parents stood up to Voldemort at the height of his power...fairly heroic thing to do. In that respect, the apple surely doesn't fall far.
Frankly, I didn't think Harry was being a terrible human being...in fact, at points, I agreed with him. Was he being a jerk at times? He sure was. But he's earned a little pettiness, I think - especially with the treatment he's gotten from day one. It's hard to feel very good about folks telling you that they're protecting you when they've done such a shoddy job for the last four years. And let's not forget, Harry's still dealing with the constant emotional turmoil of just being him, let alone the murder he personally witnessed and all the troubles he's had in the last four years prior to OotP. Turns out he's not without flaws. I rather liked that aspect of OotP, personally.