First, I like to feel welcome. Not coddled, or even nurtured; but truly welcome within your retail establishment. This is not the same as technically good service, although they are connected. And it's not found as reliably as you might imagine.
Second, I like the food to taste delicious.
Third, I like for the wait staff to enthusiastically like the food, and to be able to talk about how a dish works (in terms of flavor), and what they like about a dish. Really, enthusiasm is more compelling than literacy, I am fine with pure emotion on the subject.
And finally, I like clean. I admit that I'm fine with less-than-perfectly-clean if: (a) I am welcome, and either (b) I am hangry; or (c) all of the delicious food has been fried.