A few years ago I had purchased another car since my old one was not going to last long. 

I still had my old car and had not gotten rid of it yet when this happened.

Each day I would drive to the next town and park my new car in a residential area and walk a few blocks to get to work.

On the way, I noticed this one car that was identical to my old car except for different color and that it also had one missing hub cap.

One morning that week, I took a hubcap off of my old car and put it on this car that needed one and walked off.

I never saw the owner and the owner never saw me.