My father was an expert class HAM radio operator. I remember him teaching me this as a child and illustrating it with one of his amplifiers to cement it in my head at a young age. He took the cover off his amp which was unplugged from the wall, took a screwdriver, touched ground and then touched one of the massive capacitors. The arc created a loud bang and scarred the surface of the screwdriver.

But that didn't stop him from encouraging me to experiment while taking precautions. As a teenager I destroyed two ATX PSUs trying to add 110vac compatibility to an 12vdc RC battery charger. Third time was the charm.