I tip everyone that gives me decent service, even on top of a service charge. If the service s*cks - I don't. I know enough not to blame the waiter for a kitchen problem too. I find too often in Thailand (not the PA) that because labor is cheap, people throw bodies at service, which IMO, actually hurts attention to the tables. The waiters stand around talking, joking, and ignoring their customers. For example, I was in a Wine Bar on Soi 11 last week around 10 pm and there were maybe 8 people in the dining room and 4 at the bar. They had 7 bartenders and I just about had to set myself on fire to get another glass of Shiraz !