Timely subject. This happened just a few days ago.
I'm cleaning up a part with an x-acto knife.
The part is in my left hand. The knife in my right hand.
I've gotten to where I remove my glasses while doing close up work.
With my right hand I go to rub my eye forgetting the knife is in my hand.
Fortunately the tip of the knife only hits the bridge of my nose.
It was definitely a wakeup call!