once, and this one always gives me memory pain, i was stripping some cable lines for a residence, and i didnt have a stripper so i used a utility knife, (like a big version of a box cutter), but it right along side my thumbnail, about 3/8" of an inch. man did that ****er bleed. and it was cut with a nice blade so it bled for a LONG time. when it gets cold or i whack it it hurts like abitch...