Quote from sacredGive me a good example of successful person who keeps all his money to himself, and acts like a bitch in front of all the press and their friends, assuming they even have friends.
Firstly, that doesn't describe all not nice people. A not nice person almost has to attempt to appear nice to everyone else simply to get into the position where backstabbing is an available option. If no one will turn their back on you, they are unstabbable.
Secondly, Lawrence Ellison, Ingvar Kaprad, and Anil Ambani for a start.
Edit: I would consider those sorts of people more apathetic than nice. A nice guy should go out of his way to help people.