About 5 yrs ago....
I worked in a factory and made fabrics for the paper industry. (boring but well paid). One job involved slicing the edge of the fabric perfectly straight using a special knife (a bit like a stanley knife but it's heated). Anyway, no matter what I did, it wouldn't work, cut straight or give the required sealed edge. I lost my rag and threw the knife into the corner of the area I was in. It skipped off the floor, pinged up off a metal cupboard and rebound of the side wall to smack me in the face.

I just stood there, eyes streaming from the impact to my nose, and prayed that no-one had seen me.

the big man must have been listening because none of the four staff within the same area had spotted my idiocy. Got made up to supervisor the following month and had to train staff on the correct use of the knife. Made sure they were taught to throw underarm only.
( NooShmoo It's a fantazmagorical pile of ultra bollocks, Sat 29 Jan 2011, 9:16, Reply)