In college, it was far from being my first DIY project, but it should've been simple. Wiring the illumination for some gauges in the dash, I was laying on my back reaching up under the dashboard. I forgot that in that car the cigarette lighter was live ALL THE TIME. I shorted it out with my wristwatch. Just about welded that thing right across the lighter terminals. It got really hot too. When I finally yanked it free, I discovered how many sharp edges are in there.

Years later I did it again. How hard is it to change oil, right?

First oil change on our new 1989 Saab 900 got me. The oil filter is right alongside the back of the alternator. Who disconnects their battery for an oil change? I should have. I managed to get the oilfilter wrench up against the big power terminal on the alternator.