How about this:
One night I sat down to my sewing machine, and hmmm,, it wasn't working. It would put holes in the fabric but no thread. I just knew I threaded it right and even checked it.
I go on for about 5 minutes and can't figure it out.Finally, I did. It wasnt' threaded through the needle! I had it pulled down under the presser foot, but not through the needle hole, LOL. OMG, I was so embarrassed, even though no one seen me!
That was one of the dumbest things I ever done! LOL!