Stupidest mistakes you've made working on a car?

[FarmerPug]

ooooh sore. I suppose my new stupidest mistake is wiring footwell lights to the doorcard lights.

[martint]

while working on the escort mk1,a sea-gull sh*t on me.Got the old trusty GAT pellet gun outta the boot.took aim AND....put a pellet right through my windscreen!!!it was pissin down too!haha

[millard]

Whilst drilling a hole to fix this




I drilled through me finger. That was daft enough BUT,, I then attempted to reverse the drill to get the bit out again.
It's almost healed.

[Stain]

amazingly NOTHING springs to mind on my own cars or bikes! (ive only been doing it 9 years got plenty of time yet!)

apart from the usual forgetting filters or sump plugs on trucks my biggest mistake was putting 20litres of Diff oil in a truck on a service. sent it out. the next day i got a phone call... apparently 3000clicks IS enough to loosen a diff bung! to make it worse the truck wasnt very old and the only thing that kept me from loosing my job was the fact i went and swapped said diff internals with a written off one we had in the yard on my own time!

a guy at college wired a battery live into the cabin on his clio... didnt grommet the feed, blew a terminal off his battery

[Captain Jack]

Oh I remembered another one - here!

Funny how all of my "mistakes" are documented on this forum....