I did so many stupid things in my youth that I should have been dead many times.

But here is a more recent one. I had a block machined and was doing the assembly myself. Pistons and crank were in and I was looking over the paperwork I got from the machine shop. I didn't see anything about a sonic test. Since it was .060 over, I had ordered a sonic test. I called the machine shop and he said he must have forgot to tell me, there was a couple of thin spots at the bottom of a couple of cylinders. So I should probably short fill the block to be on the safe side. Well crap! It was already finish honed and assembled. I was running short on time, so we decided I would measure each bore in 12 locations, add block fill to 1/3 full, then re-measure after it was set up to decide if it needed to be torn down and re honed. So to keep the motor clean while I filled it, I wrapped shrink wrap round and round it, then just poked little holes in the shrink wrap where I could pour the hard block in thru the coolant holes in the deck. Looks good, ought to work, so I mixed up the hard block and started to pour. I checked the depth with a welding rod "dip stick" and it wasen't too deep. So I poured a bit more and checked it again. Still not as deep as I would expect. I step back and take a look.... Oh son of a @#%$&, I forgot to put the frost plugs in! The hardblock is running out the frost plug holes and filling up between the shrink wrap and the outside of the block, and some of it was getting under the pan rail and starting to fill up inside the crank case! So I franticly cut the shrink wrap off the bottom and sides, install the frost plugs, and start trying to clean everything before the stuff hardens into concrete. What a stupid mess! I was kicking myself for a week over that one. But surprisingly, everything turned out good, no chuncks of concrete were ever found floating around the motor and it didn't have to be re-honed.