You see, I'd heard a joke and I liked it. I was tickled by the punchline, which eluded me until the joke was finished.
A kindergartener and I were sitting at a table, counting Christmas ornaments for math centers. She finished, so I said to her,
"Hey, what do you call a boomerang that doesn't come back?"
I said, "How did you know my punchline? How did you know that?"
"Cuz ... its easy."
The tone was "duh."