There are a few crucial ingredients that go into the making of a good greasy spoon:
The mood; deer and fish trophies must match the discount carpet. The locals need to welcome you with that "what the hell..." look. And the cute waitress needs to want nothing to do with you.
The food: discount coffee must be mixed 50:50 with appropriately seasoned dish water. All food portions must "slide" in some fashion. Cheese will act as a substitute for ANY missing ingredients. And the price should reflect the grocery supply bill cause you're not paying for the "talent" in the kitchen.