From time to time I used to see a beautiful classic Mercedes coupe parked around town on double yellow lines, a blue badge prominently displayed. I had it in my head that the driver must be abusing the system - after all a disabled driver wouldn't drive a classic Merc, would they?
Then one day I saw the driver painfully dragging himself out of the car, and then proceed slowly down the road on his artificial legs, with the help of two crutches.
Hope I learned something about myself from that!