As I've said, I'm a good tipper and will continue to be a good tipper. But I must say that I have a problem with this statement. You should do a good job, provide good service, be polite and helpful, etc. because that's your job, not because you are trying to get the best possible tip. Of course, if a particular customer has been rude or obnoxious to you, that's a different story. But assuming a customer is perfectly fine but just doesn't tip well, I don't think you should treat him or her differently.
I don't work in a tip-based occupation, but I am paid hourly. I could say, "I'm just going to do the basic job since I'm going to make the same money either way. Why make the extra effort if there's nothing in it for me?" Of course, I don't do that. I do the best I can do because I care about my job and the people I deal with and its the right thing to do.
Another thing to consider... What happens when that bad tipper goes out and tells all his friends, family and coworkers what lousy service he got at your restaurant? And they pass that on to their friends and so on. I would think it is in your best interest as far as job security to keep the customers happy. Do I think its right not to tip - absolutely not. But I think even a non-tipper deserves good service.