How to slice, pit and peel an avocado without ending up in the ER

When I was in physical therapy a few years ago for a small knife injury to my index finger, I was seated next to a very nice gentleman (in front of a TV showing the Food Network, naturally). He laughed when I told him why I was there.

He showed me his hand, which had a massive scar between his thumb and index finger. It had been patched up as best could be done, but it still looked gruesome. He had sliced straight through the skin — and artery, muscle and even down to the bone, if I am remembering correctly — while trying to remove an avocado pit with a knife.