If you are dating a waitress and have lunch at the place she works and she has your table

@ABCDEF7 Here people are paid a low wage, and tips make the difference for them. If they do a good job they get a larger tip, bad service they get nothing. It is win/win.

@MisterBander I know that they are paid less. But I don't understand why a thriving country/economy can't pay a section of it's work force adequate renumeration. Here, if they do good jod, they can get frequent increments and bonuses with additional benefits from employer. They can increase the prices of their products if they can't afford correct salaries with the current prices. Being from other country/culture I just can't understand the justification for tipping system. If a customer like the services of person they can offer tip with their will, but it shouldn't be expected every time from every customer.

@ABCDEF7 The benefit is that sometimes a rich drunk guy will visit and hand over a massive tip. No employer could afford that as part of standard wages.
Also by not paying them a liveable wage the employer can have more staff, and let the tips pay the extra.
There are some restaurants here that do not rely on tips too, or they share the tips so no single person gets it all, which is kind of sad for that lady that would have had a nice bonus that day.