Today while driving my wife's car home, I tried to shift it into first gear as I pulled in the driveway. Normally this would be a fine thing to do, but her car is an automatic. The end result was that I stepped on the brake really hard, and shifted into neutral. As the car came screeching to a halt, my brain tried to make sense of what was happening, and couldn't.

That would have been the end of it, but my wife happened to be looking out the window at the time. So then I had to explain to her what I had done. Oops. :)