Only the one, about ten years ago, getting ready to go out, waiting for Aurelia to get her boots on, and I think to myself hey I've got a minute, time to cut that piece of superglue off the pred I brought from ebay.
One slip later and it was off to hospital with a U shaped cut in my thumb just over an inch long. A Taxi driver on the rank was kind enough to take us up there when we had no cash. (I found him to pay him back the next day, to which he politely refused and was glad I was okay.)
Still have a scar today, it used to annoy me as if I touched it, the scar wasn't level with the skin, but over the years its been swallowed back up and is now just a white line. Looks like I'm a Ultramarine fan. The Horror.
So yeah, message from me is never try to rush with a blade. It can get ugly.