Much humor is based on truth.

I swear that I was only joking (or at least being anhydrously witty) yesterday.

Elmer Fudd suggested that a specific one of my employees would phone in sick this morning. I told him, "No. He already called in sick once last week. It's someone else's turn."

My voice mail light was blinking when I entered my office this morning. Sure enough, it was a different employee calling in sick.