To me, there are several levels of dining out.

First-There is the fast food slop that you don't tip for anyways

Second- There are the places like Dennys. Perkins, IHOP, Waffle House ect...
those places only pay minium and the kids and older ladies that staff there try hard for the abuse I've seen thrown at them. They deserve at least a few bucks if you're gonna take up a table.

Third. The Family restaurants, be they chinese, greek, Italian, Jewish, Indian ect....these are nice meals. These deserve at least a 15% tip if not more. Food made with love is the best.

Fourth- We have our suit and tie and little sexy black dress on ,we have the valet park our car and we start off with a nice bottle of wine that the sommilier recommended. There is candlelight and the lights are dimmed. The ambience is wonderful, the curls of butter atop crushed ice is lovely as is the relish tray. We order the beouf wellington for two and have a fantastic night.
15-20% doesn't even begin to cut it in this instance......This is a special night and for a special night, you need to pay up. This is a night that you have to be happily ready to part with a $50 at least.