Does great service equal great tip$?

Anyone who has ever worked as a server in a restaurant knows that great service equals a fat tip right? WRONG...!!! At least thats what some recent studies indicate. According to these studies, servers only recieve marginally higher tips for their above average service. In fact, the implication is that most patrons tip out of guilt or customary practice anyway. Soooo... if the aforementioned is accurate, why even bother trying to rendor great service? Personally, I like receiving impeccable service and don't mind compensating the server well for it-- but thats just me. What say you?