Ouch Bert, that one happened to me when I worked as a forecourt attendant in about '78 when customer decided that was the way to attract my attention while I was checking the oil for her. Thinking of forecourt attendants, do they still exist anywhere?
As for cars, Mark, one of my brothers who worked as a mechanic for many years before he turned to landscape gardening (and incidentally was one of the best Citroen mechanics in this area - he still gets asked for help with the wierd suspension of a BX, etc.) wears his wedding ring on a chain round his neck and the ring has a bit missing. The reason for this is he managed to catch it on the starter solenoid and make contact with earth and the ring turned red before he was able to remove his hand- not a pleasant experience and one that taught him a reason to observe health and saftey rules like don't wear jewelry when working on cars.