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 blas√© 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.