Worst I've played was an ageless paladin that thought that all evil actions were really good and all good actions were evil. He thought sex was bad but rape was the epitome of love. He deemed murder the just and good thing to perform...constantly. He found thievery an art and demon worship the utmost reverence. He publicly called all good deities frauds and not in the people's best interests. He even enslaved clerics of good gods to "persuade" them to join him.