I fully support tipping. I give 20% as a starting point, with more for exceptional service, and less for mediocre or worse service. I know that the wait staff makes much less than the minimum wage, so I want to make up for that. But the tip will be adjusted based on the service, attentiveness, friendliness and professionalism of the server. Improvements should include paying a higher wage, at the very least minimum wage, to allow for customers who do not believe in tipping.