Burgers, shakes, pancakes, hot dogs, sometimes BLTs and tuna melts. That sort of thing. In Europe, the "American Diner" is usually the only place that'll serve a normal plate of pancakes. (Everywhere else it's crepes, which are completely different...)
At a diner in America, I'd be unsurprised to see some less "diner" offerings. When I go to my local non-chain diner, I order fettucine alfredo. And the article here has a good picture of a diner advertising "American and Korean food". I think part of the core diner concept is a somewhat athematic menu that is meant to cater to local tastes.
So I'm a little surprised at the idea of a diner that only has classic burgers / shakes / pancakes, but I'd have to admit those are fairly core dishes.
Yes, absolutely. They talk to you the way I expect to be talked to in a diner (lotsa “huns”), the coffee never ends, and sometimes you get to watch UFC live. The food is so easy to eat, too.
Fried chicken, liver and onions, biscuits and gravy - the breakfast options are my jam, but not really the other entrees. You can order dessert regardless though!
