Worst thing you did or encountered?

bypassing factory amp in a toyota tundra. ....... factory airbag wires (oem yellow on black) had been replaced with right rear speaker wire colors.  i was poppin wires at the kick panel to check speaker polarity and the seat belt safety bolt fires off.  scared the cr@p out of me and the counter people thought i was mad and throwing tools in the back.  $175 to replace seat belt assy.

put a new deck in my wifes car.  mixed up the illum wire with the dimmer wire.  every time she turned the headlights on it would blow the tail light fuse.  instead of talking to me she tells a friend about it and he says to just put a bigger fuse in.  after she works her way up to a 35a fuse over the course of a week, the 18AWG wire finally gives out ..... about a 8' run of it .....

that's the worst i've done. but hey .... give it a couple of months ... with my luck, somethin else will pop up.