"In the UK (to the best of my knowledge and experience) a hole in the wall place is a wall, with a hole in it (i.e. a serving hatch)," says Peg, who wonders what the term means here in the States.
A hole in the wall is "a local, small, indistinct place," says DCLindsey. "Like a small restaurant run out of a place that wasn't always a restaurant, with little to no ambiance and usually a quite casual place where you wouldn't imagine a restaurant. You don't go there for the atmosphere, or the decor, or service, but because the food is great."
The emotional connotations of a real American hole in the wall, says Veggo, are complex. "Walls are discolored from decades of smoke, when smoking in public was lawful," says Veggo. "Customers and staff have known each other for many years. The winning lottery number is prominently posted. There is a collection jar for the most recent local tragedy, well stuffed with wrinkled bills by hard-working folks with calloused hands."
Eateries with a literal hole in the wall are not unheard of in the United States, though. "Miami is full of Cuban 'coffee windows' where you walk up and get the best sugary espresso shots or cafes con leche or guarapo (fresh-squeezed sugar cane juice), always with croquetas de jamon or empanadas or pastelitos or quesitos," says Big Bad Voodoo Lou. "No public entrance or seating, just the window."