I haven't cut myself bad...in several years, but that last time, I had a brand new Spyderco serrated edge close on my hand.
I was attempting to cut a strap off of a box at work, so I flipped the knife over and slid it under the strap and pulled. I didn't realize the strap was reinforced with metal, so when I pulled back, the blade slid out from under the strap and closed on my hand...due to the fact that I also didn't realize my finger was depressing the lock button from the pressure of lifting the knife as I pulled.
When I went to the clinic to get sewed up, the worst pain I had ever felt was when the nurse cleaned the inside of the wound by scrubbing it like she was trying to cleans pots and pans with an SOS pad. I was literally crying out like a little girl, LOL!!
It could've been worse. When the blade closed, it missed the main tendon that runs across the top of my first knuckle by mere millimeters.