40 years ago my father in law taught me how to use a chain saw safely. He knew what he was doing, he was MD of the UK's only chainsaw manufacturer at the time (Danarm). He took a very dim view of safety equipment. He felt that knowing that the slightest error could cause horrible injury or death was the best way to avoid becoming blasé about their use. I still don't use any safety kit today when using a chain saw.
That's true I suppose, I never had any formal training with a chainsaw and never wore PPE, then whilst cutting down some conifer hedge a gust of wind blew the windbreak fabric on the fence onto the back of the blade which then flipped back and smacked me in the forehead, chain still spinning.
I was told had it hit any soft tissue I would have been more seriously injured than I was.
Now I do wear PPE, but am also far more aware of what can happen outside my control.