I think that maybe going through all that just made him stronger as a person. I also think that some of his mom and dad's personality lives within him, thus making him an amazing and strong person. I know some people that have been through neglect, abuse, and things like that when they were younger, and they are some of the nicest people I know personally. It's like none of the bad stuff ever happened to them, yet you can still see that they have been through an extreme situation by the way they act. Bad things happen to good people, but it only makes you stronger in the end. I think this is the case for Harry. He is so strong, and even though he really doesn't exist (as much as we wish he did) he's an inspiration to people who have been through bad things and have come through and prevailed.