When I was six, my neighbor used me as his spark testing assistant on a lawn mower he was working on. I have respected plug wires ever since. My first car was a 72 Cutlass and I discovered the joys of adjusting points. The screw driver flew across the yard accompanied by unrepeatable oaths. Went to the junkyard the next day and got an electronic setup to replace it.
That's smart for more than one reason. :^)