What's the funniest or dumbest thing you did?

Had to think about this one ... so many choices! Well here's some genuine stupidity for you:
Was troubleshooting an amp that I had built myself completely from scratch. Somehow I connected the output test leads back onto the meter that I was using to monitor the input. Powered on - went into total oscillation, & then kapow a cap exploded. I was so royally ticked at myself!
Turned out to not be so bad after I decided to gut the whole thing then redesign & rebuild it. The result was quite rewarding.

Grade nine electronics class; I was trying to take a mono turntable, install a stereo cartridge, and run stereo inputs to a tiny Radio shack amplifier. I wound up wiring AC power into the turntable cartridge. When the electronics teacher saw what I had done, he laughed so hard that he had a seizure and had to be taken to the hospital in an ambulance. Do I win???

A few years ago my mother did some laundry during her visit and since it's was warm day, she decided to hang the laundry outside. I wasn't home to help her so she made a cloth line using my Kimber interconnect cables. I didn't realized my cables were missing until a few weeks later seeing it tied to a post and a tree.
I was wondering why my shirts were brighter.
Rich

True to style, I have beheaded a number of cantilevers, a Sumiko BPS @ least 10 times-- at the end, I was offered reparation for free (by Mr v Den Hul, no less, taking pity on me). Fortunately I never killed my expensive Clearaudio.
Better still, I lived for 2 weeks w/out real bass below 83Hz (2nd amp was not operating), without catching on. Not only did I not realise that 8 woofers were not moving, I found the sound very clear -- but a bit thin -- all of a sudden. Even better, I was SWITCHING ON the amp, without checking if it had actually powered up!!! It couldn't, it wasn't plugged in the mains
I FIANLLY caught on that the lower register was lacking and was considering speaker placement yet again, when my wife called me one day, frantic, to tell me that the "black amp" wouldn't light up...

So much for these here "golden ears"... and to think that people regularly provide me with components for my "erudite evaluation". You bet :)! So now you know...

I used a blow dryer on the midrange of my old LFT-VIIIs and then spent $200 for a total of 1 meter of purled interconnects. Oh wait, I'm supposed to do those things....

How about buying bottled water on a rainy day? I'm sure that's the penultimate sign of a civilization hurtling towards self-destruction.