Let me start off by saying you have to watch this movie in IMAX-3D, the experience is awesome. And once again a movie (director) tells our species we are disgraceful. In Avatar, James Cameron takes us to a world where humans attempt to take over without hesitation. I'm sure there's a back story where the scientists talk to the native Navi but this movie is about courage and good will.
So what constitutes a good person? A good person knows what's right for others even though it's wrong for your own friends, family, etc. (and vice versa). We always think about the people we meet and whether or not they will be our true friends; sometimes they will sometimes they won't. We always assume people have hidden agendas and sometimes that is right. In the end, we will see what kind of person they are and if they were given a person. In Avatar, Jake Sully realized his true calling and made a choice to become part of the Navi.
Moral of the story: humans suck haha.