...The other thing I'm thinking is that if your sales tax is 5% and you tip 20%, then you're paying a bit more than 25% over what shows on the bill. If I tip 20% post-tax, I'd be adding more like 38% to the bill. ^^; This is not so much to say that I have more right to be cheap but that economic theory dictates what's normative/average. Too, lower taxes tend to correspond to lower minimum wage, and vice versa.