Just to expand on this because of the required taxing on tips it actually brings down what CA servers actually make. Basically CA started a rule a server has to claim at least 10% (I could be wrong about the amount as it has been a while since I worked in this type of situation) of what they sell in a shift, so if you sell $150 in food you are automatically taxed $15, 10% of that amount, but the terrible thing is if you actually make less then that the goverment does not care you still pay your $15 even if you make $1, and on the other side if you make more you are required to pay 10% of that amount as well.
This system has hurt some of my friends. One went to work and ended up with a very large (25-30 people) for most of her shift taking up her whole station. They loved her, they laughed with her told her she was great everything. She brought the check which by her employers rules had a 15% added large group graituity and they got mad. She had the manager explain that though that was the rules they would allow them to adjust the tip to what they wanted. They ended up leaving her NOTHING. They punished her for the companies policies, ones stated on the menu and when they were seated. So after the bill was figured she actually paid for them to eat as the goverment still believed she would get the minimum tip.
Basically my main point, if you ever chose not to leave a tip, because your server was terrible, please inform the manager why. If the service is bad enough to give them nothing it is bad enough to get a manager. I have only done this twice in my life and one of the times I still tipped the bus boy directly since he did everything for us but take our order!
Can I also take a moment to say how much I hate bathroom attendants!!!! It's not the people themselves, it's just I find the idea really creepy and I try to be nice but to not use any of their stuff cause it's just too odd.