Y'uns can eat burgers, if you want, but a real diner always has full meals--diner-style, with sides and salad, and desserts--

You should be able to eat breakfast, lunch, and supper there, the coffee should be good--you should be able to get "real" food(not cute food), and plenty of it, and the service should be fast. There should be a counter, newspapers to read, and a jukebox. Also, ideally, the diner should not be self-conscious, which is to say, it shouldn't be a 50's theme park attraction--it should have lots of glass and stainless steel--and, in the best of all possible worlds, the waitress should say, "What can I getcha, hon?"