Ok, haven't read the other posts yet, but here's my opinion. Tips should be received based on performance. They should NOT be mandatory. In my eyes, every waiter or waitress starts off with a 20% tip and it is adjusted from there. More for exceptional service, less for substandard service. And I have left little to no tip (1 penny so they KNOW I didn't "forget" to tip) before if the person deserved it. That's just my personal way of tipping.