if our waiter/waitress is friendly, helpful, refills our drinks w/out asking, or chips/bread (as applicable); our food comes out correct; he/she stops by 1 or 2 times etc.
we'll usually give 30%; and on our way out (or before we leave) ask to see the manager and let them know that he/she is doing a great job.
it's funny to see the waiter/waitresses reaction when we ask to see their manager (if we decide to). They usually come back blushing etc; and you can tell they appreciate it.
god knows I couldn't do it; putting up with assholes like Pastor ****face.
Life is 99% inspiration, 1% Perspiration, and 1% Attention to Detial.