Irrefutable proof that I am an idiot

We are a weird American family in that we have only a single car. (Oh, the horrors! Yes, we alone are responsible for the collapse of the American car industry because we own only one car, paid it off, and continue to drive it instead of leasing or constantly upgrading.)

 I took the car in to the mechanic this morning for an oil change and tune-up, and, by the way, the car is making a rattling sound, can you investigate that? Well, that rattle is luckily not the car's death rattle, just a very expensive rattle, and so I decided to walk home because there really isn't any interesting way to pass four hours in the local of the mechanic shop.

I walk home from the mechanic (about 30 minute walk), approach our house, and my first thought is "hey, the car isn't here. I wonder where Oscar went?"