I think that's like asking to give a precise definition of sea water. It's difficult, but virtually everyone can tell apart sea water from fresh water in a blind tasting. In the negative, I'd say a good parent is someone who isn't self-centered and doesn't humiliate his child because of his own insecurities. Someone who doesn't make his child doubt himself. I used to believe that an acceptable parent was just someone who didn't physically abuse his child and provided food, shelter, clothing and schooling. Now I know that's not enough. The children of openly alcoholic, drug addict, physically abusive parents are "lucky" (in a very twisted way, of course), because when they share their experience most people will understand and empathize. But the true "genius" is when you can humiliate, ridicule, exploit and psychologically abuse your child without overstepping the socially acceptable boundary. Achieving that "sweet point" where you can maximize the abuse and the damage while maximizing the deniability. Because when the child talks about it, everyone around will just shrug and say that it was a joke, that it was nothing, that it was the child's fault, that maybe the child didn't perceive it accurately, that that's the way things are, that it's impossible because your parents love you dearly... The true "genius" is getting away with as much abuse as you can and making your child believe that it's his own fault or that it's for his own good.