I'm assuming you are being facetious... :o) The joke was a good one. :o) Yes, I was joking, and yes, that was a good one.
When John Baird and I worked together in 2003, we had a co-worker who would send out jokes every day. I would pull an Edith Bunker and reply that I didn't get the joke and I'd try to insert logic into the joke.
(Unlike Grady's joke, sometimes my reply would generate more humor than the original joke)