A "well organized" psychopath won't treat the waiter like shit, because it doesn't get him anything, whereas being polite and seemingly forgiving around people (like you) whom he wants to think well of him does get him what he wants.

Meanwhile he'll be playing the long con with you - manipulation and mind games that can be incredibly subtle. I had the misfortune of working with one of those for a few months - we almost became co-founders. Recognizing and getting out of that situation before I got in any deeper was one of the smartest moves I've ever made.