I've gone long stretches in Chicago without a car, so when I'm in a borrowed vehicle I always have an impulse to go do some errands. Even when, as this evening, the errand I'm on is to get parts for my own car so that I can fix it and then drive it anywhere I please. Even then, behind the wheel of a friend's minivan, I had a moment where I wondered if there was anything else I needed to do while I had this mobile power.