After finishing an out-of-town errand, I discovered that my
car wouldn't start because it was out of gas. A passerby
told me there was a service station a half-mile away, so I
took a gas can from the trunk and trudged the distance in
the sweltering sun.

The attendant filled my two-gallon can, and I lugged it back
and poured the gas into the tank. But when I tried to unlock
the car door, it wouldn't open. Just then, I noticed an
identical old car parked a short distance away. That was my
car; I had filled a stranger's gas tank.

Wearily I walked back to the station. "You know," the
attendant suggested helpfully, "Instead of walking back and
forth to fill the tank from the can, you could put a couple
of gallons in the tank and then drive the car here."