In the technical sense, the comic writer is a cat on a hot tin roof. His invitation to perform is liable to wear out at any moment; he must quickly and constantly amuse in a short span, and the first smothered yawn is a signal to get lost. The fiction writer, in contrast, has much more latitude. He’s allowed to sideslip into exposition, to wander off into interminable byways and browse around endlessly in his characters’ heads.
S. J. Perelman