Accidents happen when you try to cut corners. You don't have something clamped down or you try to cut something too big and awkward. You climb on a ladder that isn't steady or maybe only supported by the top rung on a small tree. You don't bother with the safety glasses because it's a only 10 second cut. The list goes on. I once decided to use an electric buffer on a brass lamp without taking it apart and removing the cord. Guess what happened.