The anatomy of chainsaw respect fail

This recent incident with a chain saw (a Michigan man accidentally hits his wife with a chainsaw, his sheriff's deputy neighbor is quick to responds to the scene, but it was too late) resembles the poor judgment using a chain saw in one of my cases: A man was doing minor yard work using his lightweight chain saw. After his was done, he realized he always wanted to trim unsightly boards protruding from his patio and abutting the side of his house masonry. He thought he could just nip the boards with the round end of the chain saw. Except he underestimated that physics of the chainsaw. As soon as he revved it up and touched a board, in a blink of an eye that chainsaw's round end bit the board, climbed onto the masonry and hit the man on his face, to the side of his nose. He was very lucky that he and his family agreed to the full reconstructive cosmetic surgery, which was very professional. It has bee less than a year and he has very little marks left that would testify to the violent accident. He says he never suspected chainsaws to have the unpredictable tendency to kick back.