A lot of very good points being brought up on both sides of this argument. I do tip and tip fairly well imho BUT it is earned...not just deserved for slapping down my plate of food and walking off and forgetting about me.
I absolutely don't agree with NOT tipping unless the service is terrible.
Below average service warrants a below average tip and above average service deserves an above average tip...pretty easy I think.
I also DON'T send food back ever...too many horror stories on that one.