Oh, I think that's because we're embarrassed. We don't know how to cope with the situation. Perhaps we are even a bit frightened we might get like that, so we laugh. What about the custard pie routine?
Brow furrowed, Frank inclined his good ear still closer to the door, listening very hard. There was a pause, and then the man called Wormtail spoke again.
UNIDNETIFIED MALE: If you don't finish your work by the time you get off in the evening, there's no choice but to come in early in the morning voluntarily to finish it.