In the United States, in at least some places (the ones where I've worked in restaurants) it is legal to pay waitresses and other restaurant staff less than minimum wage.
That's why I always tip. That and these additional reasons:
- I like being served food. It's sooo much better than trying to make my own.
- I like being cleaned up after. It's so much better than having to do my own dishes.
- I know that, in most cases, the wait person is doing their best, with minimal rewards.
- I've been a waitress - I know what it's like to have limited job options.
- Generosity is the milk of human kindness. When I have the money, I share it.
So, tip those waiters and waitresses! Remember that they will split their tips with the kitchen staff and bartenders - they don't get to keep the whole tip.