i hate the idea of tipping, i accept its the norm in the US, but wont be told how much to tip, as a rule ill tip $10 for the waitress at a breakfast buffet, or $20/25 at somewhere like the rainforest or T-rex, but only if i get good service, if we're waiting ages, or theres an avoidable problem then theres no tip, bell boys, bus drivers or barmen $1 per item/or drink, taxis usually $10;
once went with my brother in law and his family, we couldnt understand why he always took so long at the bar, i went to help him carry the round back on my way back from the loo and realised he wasnt tipping at all, but making the exact total up from his change, the barman would even stack glasses or load the fridge before serving him, his missis explained to the barman that he didnt understand and gave him a backpayment then things ran alot smoother.