What is the dumbest way you’ve been injured?

oh ... not so long ago, I was trying to put a cartridge into my favourite fountain pen.. and the cartridges were cheapo rubbish and so they didn't pierce like they should.. so I had the bright idea of finding something really sharp and pointed to manually pierce the end of the cartridge.

I did think while doing this.. oh, it would be a really bad thing if the really sharp pointed knife were to slip.. .

And then it did! It went right into my thumb because it was very sharp and I was applying a lot of pressure. Half the depth of my thumb.. it wasn't pretty!