I always love it when we get a waiter/waitress that is new to the job. They are usually very well mannered, and quick to fill your water glass up. So they may not have everything straight on the menu, but you can tell that they are trying. I like to give them an extra big tip for the effort.

I really hate it when I order an H2O (what I almost always drink) and they never come to refill. That if anything will make me tip less than I ordinarily would. But if the waiter/waitress has a huge crowd and obviously making an effort, then that is OK. But if they are on the other side of the counter leaning on it, and yakking at somebody...grrr!