Bilateral Thinking Puzzles

Q: A man lives on the tenth floor of a building. Every day he takes the elevator to go down to the ground floor to go to work or to go shopping. When he returns he takes the elevator to the seventh floor and walks up the stairs to reach his apartment on the tenth floor. He hates walking so why does he do it?

A: The ice cubes in the man's punch had been poisoned.

Another

This is another thing that seemed funnier a third of the way into writing it, from the Surrealist. 19th August 2005.