Sometimes, even us old dogs need to learn new tricks. Or we need to be reminded by God that you can get hurt if you're not careful.
Some time back, I was cleaning the dynamic jaw section of a vise that I was restoring. I had clamped it in my vise to work on (see first picture). While I was wire brushing that jaw section, it slipped out of the vise and crashed onto the floor. Thankfully, it didn't hit me.
So I blocked and re-clamped my workpiece in the vise (see second picture). So the lesson here is to test the clamped workpiece before starting to work on it.
Any other "Close Call / Lesson Learned" stories out there?