I do tip 20% unless the server is pretty bad. I usually judge by water. If I have to ask for more water, I generally tip less than if the server can see I need more and brings it without my asking. Plus I tend to tip more, percentage wise, if I eat out at breakfast, becasue they have to do the same work as at dinner, and breakfast is generally much less espensive. I'm not a fan of the tip jar at pizza places, when they are not really serving, just running the register. I REALLY hate to wait for the check when I'm finished eating. I wish there were some sort of MAC machine at the table where you could just pay and leave, instead of having to wait till your server brings the check and then wait again till they get the change or charge slip.