I set my first Arduino on our washing machine, which was my platform for demos for my family. I set it right on an area with chipped paint and exposed metal. I

I set my first Arduino on our washing machine, which was my platform for demos for my family. I set it right on an area with chipped paint and exposed metal. I eventually figured out I'd shorted and destroyed the 7805 regulating the DC input to 5v. My first in-the-field electronics repair was to remove it, bodge it, and live with a USB-only Arduino. I still have that Arduino; it's a reminder of the first time I let out the magic smoke.