The "crappy" in The Crappy Restaurant Sketch refers to the state of the restaurant, not the state of the sketch. However, it works both ways, which has caused some confusion.
The Crappy Restaurant Sketch was a sequel, part two of a dilogy, to The Fancy Restaurant Sketch. In part one, the customers get instant service & food - so fast they can't even carry on a conversation. Then they get slammed by high prices so they do what anybody in a similar situation would do. They leave. The Crappy Restaurant, on the other hand, is a seedy second-class institution where it takes forever for them to get their food and they get crappy service to boot.
The innovative part to this sketch is how we depicted the passage of time. How do we show this taking a really long time without actually subjecting the audience to more of the sketch than absolutely necessary? How do we do five hours in one take? The answer was clear: keep moving the clock ahead. Since this was a one-take wonder, we set the clock over on a shelf, conveniently nowhere near the action, requiring the cameraman to pan about 90 degrees to the left every time we wanted to show the passage of time. Despite the vomit-inducing pans, the out-of-focus shots of the clock, and the tripod-free shakiness, people still understood what was going on. The problem is that its just not funny.
Okay, aside from all that, have you ever gone to an expensive snotty restaurant? It takes forever to get your food. It doesn't even have anything to do with the number of people in the place. On the other hand, have you ever gone to a local hole-in-the-wall? They usually get something on a plate in front of you within minutes. Sometimes they even make it right in front of you. Apparently we got it exactly backwards. I have no idea what we were thinking.