I'm with Sumo. I HATE HATE HATE the idea of tipping. It makes me sick. I wish we were like Japan were tips are not expected and turned away. You get great service no matter what. With that said, I still tip because I don't want to seem like a dick, and because it's 'expected', which pisses me off. Not to mention this country has the worst customer service I've ever encountered. It's almost as if people are bothered that they have to wait on you or help you out.
If everything goes good, I'll leave double the sales tax. If it's bad, I have no problem leaving $0. What really gets me though, is the sense of entitlement from people in these service type jobs. I don't care if you're just 'trying to survive'. I must have missed the part where that was any of my problem. If it's that bad, go find another job.