How about this? When you stiff your server, the next time you turn up at the restaurant, you run the risk of having the server, bus boy and chef do unspeakable things to your food before it arrives at your table...
Wait staff with that kind of attitude will show it in the service. If any place is bad enough to leave a small tip, it's obvious to me that I won't be going there again.
It sounds like you have done such "unspeakable things."