In Cheek

You what I really hate? I really hate taking a bite out of my cheek.  I was just sitting and munching away on some salad (for a change) when I just took a whopping great chunk out of my cheek. Blood everywhere and the balsamic vinegar dressing did little to sooth the pain. I hope it's OK for vegetarians to eat bits of themselves. Last thing I need is for the veggie police to harass me while I'm suffering. Why does this happen?  Surely evolution would have taken care of our nipping off bits of ourselves.