I've pointed this out before a few months ago and i had a lot of people supporting this theory, but we still don't know for sure if there is indeed a factor that decides all this.
I've said that this "personality"-factor has impact on the star-rating -> Defense, Amount of fouls, amount of shots and amount of personal fouls. You could say star-rating and fouls are connected to Defense, so that the personality-factor has a significant impact on the players defense in general.
Some say these differences has to do with experience, but i've seen players perform worse with the same set of skills and different experience. I'm not saying that it doesn't have an effect whatsoever, but you sure can't link it all to experience.