Eatocracy has a nice blurb about treating waiters and waitresses with respect. Not grovelling, just treating them like human beings.
This short article brings up the point that it is insulting to expect that career wait staff are down on their luck or can't find anything else to do. Compare the service you receive from professional waiters and waitresses to the service received by the person who does not take the job seriously, and you will be willing to wait for a table in the professional's section!
Poll at the end of the article: