One time when I was walking in Central Park, a branch fell from a really tall tree, perhaps a 50- to 60-foot drop. A squirrel was on that branch when it fell, and the branch hit the cement path with a loud thud. The squirrel lay there on its back, quivering. I knew it was totally screwed. Its back was probably broken, but it was clearly still alive. "Fuck," I thought to myself. "Look at how much it's suffering. Should I kill it to put it out of its misery?" I stood there pondering t...