I promised two more stories, and here they are:
In another thread I talked about a failed experiment of mine which involved a capacitor. I was probably about 14 years old, and I was very interested in electronics, but I knew very little about it. I tried to build my own supercapacitor; I used some construction made out of two plastic tubes, where one tube was firmly fitted inside the other (the tubes were some distance apart). I attached foil to the inside of the outer tube and to the outside of the inner tube, nice in theory, not in practice. I tried my "supercapacitor" by connecting it to a 12V car battery charger. For a second or so, it seemed to work fine. But then it suddenly exploded, and blew out a fuse in our house. Luckily, nothing worse happened. I haven't tried building any capacitors since.
Another stupid thing I've done involved a firework rocket. I was probably about 13 years old and I thought I was young Wernher von Braun. I wanted my rocket to launch, explode and then return to Earth safely. I selected the biggest rocket I could afford, made a parachute out of a plastic bag and attached and "secured" it to the rocket in some way. I don't think I expected the thing to work, but I was determined to find out. On New Year's Eve it was finally time for launch. At T minus 5 seconds we had ignition, and at T minus 0 we had launch. Off it went, so far so well. At about T plus 3 it started to look like "Houston, we have a problem"; the force from the drag must have pulled the parachute loose, making it unfold during mission. Rocket+parachute=unknown trajectory. My spacecraft then took some weird turns, and then started to prematurely head back to base. This forced me and my friends at Houston Control to hastily search for cover. Finally the craft "landed" in a garden some 10 meters away from us, and then it exploded into a large number of green and bright objects on fire. The garden lit up like a scene from Star Wars. Nothing worse happened though, but I gave up my rocket building career.
I've also been shocked twice by 230V (AC standard in Sweden). Both times involved repairing a mains distribution block with the cord still connected to the power outlet. This taught me to always check if power cords are connected or not.