Just wondering how people classify. One of my favorite places in Las Vegas is Lotus of Siam. I see lots of people calling it a hole in a wall. Sure it's in a dingy strip mall with a bunch of other restaurants and retail shops but once you're inside, the waiters are all dressed nicely in standard issue black and white. There's actual cloth covering the tables, not bare or plastic. There's glass and stemware for water and wine.
Maybe it's because I'm more geared to mom and pop family run places for daily fare and high end dining is special occassion. But I just don't consider LOS a hole in a wall.
To me hole is a wall is a place that is extremely non descript. Plain uncovered or plastic covered tables, waitstaff in regular clothing, plastic cups or the cheapest barware available for water. You get the point. That to me is a hole in a wall.