Bilateral Thinking Puzzles

Q: A man walks into a bar and asks the barman for a glass of water. The barman pulls out a gun and points it at the man. The man says 'thank you' and walks out. What happened?

A: The man is a travel agent. He had sold someone two tickets for an ocean voyage, one ticket round-trip and one ticket one-way.

Another

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