I was working in a body shop & a guy was working on a pickup & it had a piece driven down in the vent just below the windshield ( Old Ford Pickup)
So, I decided I was just gonna straighten it up some, it wasnt on the work order, & I took my dent puller tool, just a wire with a 90 on the end & a T handle, & put my elbows on the fender & hooked the wire under the part & started applying pressure. I was Maxed Out when the wire deflected & it came loose & I smashed myself between the eyes with the T handle, knocked myself backwards across an empty stall,, & I looked around & there was NOBODY in the shop, I was alone!,, So, naturally I went to tell them,, that was too funny to not share,

I heard about a guy who pulled his Savage up to the gas pump and hopped off only to have to scramble to catch the bike because he forgot to put the kickstand down. What a maroon!  

I used to have an Audi Fox and very few tools.  The muffler needed replaced and I had the car on the factory jack under the rocker panel.  It was just high enough that I could barely get under the rocker panel and reach the U-clamp...and the nuts were very rusty and I had to put Vice Grips on the nuts.  I was just able to get one arm on the Vice Grips and pulled.......nothing.  I rearranged myself under the rocker panel and got both hands on the Vice Grips....and the nut was about a foot from my face.  I pulled as hard as I could with both arms......and the bolt broke.  The force of both arms pulling was immediately transferred into a motion that brought the Vice Grips to my forehead with a loud "THWACKKKKK" (Well.....that was the sound vibrating through my cranium).

I had a huge goose-egg on my forehead for about a week!