Tipping on the percentage of your meal is over rated. For instance, let's say you bought a hamburger for $5. Or you bought a full steak dinner at the same place for $20. You are going to get the same service from either one. Why pay more just because you ate steak? Therefore, I tip according to how many people are at the table, and the service, not the price of the meal which will change each time I go in. I work at a casino. We all depend on tips for a living. But there is no 'correct' way to tip us. And it's amazing that the ones that win little, tip more than those that win alot. When friends of mine come in, are they obligate to tip me? I say 'no'. Basically, tipping is necessary because the employer is too cheap to give you a decent salary. So many of us have to rely on total strangers to make a living. I have noticed that some celebrities that own restaurants are now advertising that tipping is not necessary in their establishments because they pay the employees what they are worth. Kudos to them!