I've found that tipping can be the best money I've ever spent. My wife and I go out to eat pretty often and we tend to go back to the same places. You can tip $4.50 on a $30 meal or, for an extra buck-fifty (assuming that you got good service) and a smile you can make a gigantic impression (I tend to tip even more for small meals or split meals). I don't know how many waiters/waitresses, now, deliver my preferred beverage *as* I'm being seated, know exactly what I like to eat and drink with all my little hold-the-mayo/ add-a-squeeze-of-lime-to-my-diet-coke adjustments, and provide a suite of little extras. I eat at one dinner house where the owner/server brings samplers of any new rum that they get -- gratis. I know several waitresses who regularly comp our salads or sodas and ice teas. I've even had entire meals comped. All that for a smile, repeat business, and a dollar or two of extra tip money. To me, it seems silly *not* to tip really well when you get good service.
Of course, I tip very badly for bad service. That also has the desired effect: those servers don't want me as their customer (but the good ones do).