I've been cutting trees for years. I'm not a newbie. But as careful as I was, I got hit by a "widow maker".

I notched and back cut a fairly large tree. It was perfectly balanced. I shut down my chainsaw and set it on the ground, and then pushed down the tree I cut with one finger. The next thing I knew, I was laying on the ground, paralyzed.

Here's the full account of it, link below.