Aw Snap---I agree with you! If I were a waiter and I knew certain ones just didn't tip 15 to 20 % for good or better service, I wouldn't love serving them, especially if I could make more $$$ doing the same thing for someone who tipped well.
I knew a waitress at a Marriott who regularly got a party of 10 plus who stayed at their table for an entire evening ordering drinks and enjoying live music. They typically stayed for 4 to 5 hours! She would get no more than 15 or 20 dollars for her efforts. She was regularly distressed when they'd saunter in. They were very sweet people but lousy tippers. The other waitress I knew there did the same amount of work and was thrilled with the tables, the tables my party generally stayed at. Eventually, we began to ask for the other waitress just because we felt awful for her.