From the server’s perspective, they may have a financial self-interest in flipping tables as fast as possible. More parties that use the table = more tips = ability to eat and pay rent. Secondly, from a customer service standpoint, there are just as many people who are incensed if they don’t receive service RIGHT AWAY!. “OMG, that waitress, she didn’t even come by to ask if I wanted drinks! The nerve!” they might think. If the waitron comes by too soon, you can always ask her to come back later and be pleased at the fast service, but the more needy customer will be angry if not served right this minute, so the risk-reward ratio calculation tells the waitron to err on the side of fast service.