L.C.'s Hamburgers, Kansas City
Lots of places advertise as having "old-fashioned" burgers, and when you try them, you find that the term has lost all meaning (sort of like "premium" or "quality").
L.C.'s makes no such claim, but if it did, it would be completely earned. Their burgers are a time-warp, to back when heart disease was barely acknowledged or understood. The fatty, greasy goodness bombs your tastebuds and then flows through you, satisfying you, killing you. Since discovering this place up in the KC northland, I haven't been able to bring myself to visit a burger chain. I swear it's not snobbery. It's conscience!
There's other stuff on their menu - hot dogs, chicken sandwiches, an Italian steak sandwich - but really, deviating from their core product is the act of a crazy person.