I don't work in the industry, but I eat out enough to have an opinion here. I agree with those who say that good service doesn't necessarily equal good tips, and vice versa. For the most part, people are going to tip whatever they normally tip unless the service is either extremely good or extremely bad. I usually tip 20%, and even though I'm a decent tipper, I wouldn't say that I receive good or bad service at restaurants in any different proportion than I receive from employees of bookstores, banks, doctor's offices, etc. Clearly, servers can be motivated and compenstated by other means than the gratuity. The gratuity system is completely antiquated, and my only guesses as to why it's still around are: 1) it allows restaurants to shirk responsibility for a significant portion of their employees; and 2) servers generally aren't doing to bad under it either.