As already explained they only make about $2 an hour directly from the restaurant and absolutely rely on tips. It would be absolutely rediculous to expect one to live off of that wage especially if hours are limited. Is this really all that difficult for some of you to wrap your head around? There are plenty of cases where a "better job" isn't an option for a multitude of reasons and if people didn't tip and waiters only made $2 an hour, you wouldn't have anyone to give you your food. That Burger King analogy was quite weak by the way, they get paid at least minumum wage, unlike full service waiters, who also have much more demanding jobs so don't bother with that arguement.