Why We Say "Waiting for the Other Shoe to Drop"

Waiting for the other shoe to drop means "anticipating something that has yet to happen." An old story may explain the origin of this phrase: A man staying in a boarding house is getting ready for bed. He removes one shoe and lets it fall to the floor with a thud, followed by silence. The neighbor downstairs gets annoyed waiting for that second thud that doesn't come. This is part of a complete episode.