What's your biggest, best, funniest most bone-headed move related to your car?

a few of my own highlights:
>rebuilt and installed a bmw 6 and forgot the headgasket (hanging on the bench pegboard)
>forgot the clutch disc on a clutch job trying to beat the book
>tightening up something in the front end, socket let go and knocked myself out cold when the super long 1/2" drive ratchet hit me in the face
>backed my 69 barracuda into my 64 dart in the driveway, stone. cold. sober. caught the DS edge of the finish panel right on the money of the DS headlight ring-- years ago when neither of these things were available.
>forgot to tighten an oil filter and blew it clean off along with the mounting threads.
>360 pan on a 318 (thankfully caught while still on the stand)
>forgotten the oil slinger more times than i care to admit
>pulled pans back off for any number of reasons: forgot to check [rod, cap, etx torque] off the list or have an oil pick up on the bench and not 100% sure if that's the used one
>removed a motor and torn down because i put the wrong rings in it (before lighting it off)
>blown mufflers of all degree and manner
>lost a wheel and axle at speed on a 7.25 (totalled the car, humorous now looking back)
>all the usual: lost hair from carb back fires, oil slicks from forgot to put in drain plugs and/or overfilled because: derp, forgot. broken bolts, punctured seats, headliners, gacked paint from a tool slipping or a part dropping.

[**this list is ongoing and still developing**]

but i've still got all my fingers and toes, only minimal scars-- both physical and emotional

and to the guys recalling fleet work: it's still the same dudes. guys replacing tires with 500mi and refusing to replace 50 yr old tires. a bunch of flat rate freddies doing bone head work (well, that's what came out so that's what must go back in!), finger tight jimmy, andy overtorque, sloppy joe and careless charlie are all still on the payroll.