Thankfully, when I whacked my thumb with a knife* it looked a lot worse at first, when I was freaking about having whacked my thumb with a knife. Then later, after the band-aid and the panic and some dinner, and calling the nurse help line, I looked at the wound and thought, oh, okay. Whacked, but not cut off completely.
Time, perspective, and also a full stomach. Better than stitches!
*What is it with us right now? I slashed my thumb, am recovering from the flu, and Dyami has a broken rib from soccer. Luckily, we seem to be careless only with ourselves.