Fast 90% of the Time

This comes from watching way too many episodes of Mystery Science Theater 3000.

There are some films that not even the MST3000 people can make funny. The dialogue may be preposterous, the special effects execrable, and the plot full of holes, but the MST3000 people are often still unable to make the film funny if the pacing is just... too... slow.

If you want the audience to really get into the absurdity of the moment, you need to move fast enough to keep them from wandering. Most of life is way too normal to be uproarious. Comedy needs to move even faster than other forms of storytelling/movies to keep the audience interested.