Tipping

Hey,
When I go out to eat at restaraunts, I usually tip about 20% of the bill (before taxes).
I think thats fair IF THE SERVICE IS GOOD. If the service sucks, eg: the server doesn't ask how everything is, or if I have to ask for refills on coffee or pop, then I'll tip a smaller amount. I don't like the idea of "auto grats".
A restaraunt in Texas recently locked a family inside a restaraunt for skimping on a tip:

http://eatocracy.cnn.com/2012/05/10/...tory-gratuity/

What 's your policy on tips?
What happens when to go to a buffet where you get the food and the server brings you the drinks??? Do you still give a 20% tip?

I remember the last time I didn't tip, me and my cousin went to a 24 hour truck stop at around 11pm and as we walk in the door and the waitress that was there gave us a dirty look. We were the only ones there and had interupted her conversation with the cook. Well she goes over and throws the menus down on the table and asked what do you want to drink, and she said it in a sort of hurry up and GTFO sort of tone.

I order an ice tea like I always do and my cousin orders a pepsi, she brings back the drinks and I said I wanted the mexican plate and my cousin wanted the chicken fried steak. Well she says something about we can only order burgers or sandwiches because blah blah blah so we each get a burger, and we had to ask her for a refill on the drinks when she brought our food out because she just hid in the back all night and never checked on us.

Then it gets good, a few minutes after we get our food a group of 5 or so walks in and orders items off the part of the menu she just said was off limits to us.

By the time we finished eating the other table had just got their steaks.