I was waitressing one day and a couple walked in, asked where the restroom was, and went to the back of the restaurant to use it. This meant walking past the bar, weaving between table after table with napkins, forks, etc (although no one was eating at the time). Then when they came out, I said, "So will you two be staying for lunch?"
The woman gazes around with an absolutely open- mouthed look of wonder and says, "Oh, is this a restaurant?"