There ought to be a warning on this thread. Seriously.
First year of my apprenticeship, one of the simple jobs was to part off, face, drill and machine cut (M12) a piece of bar. Even after all the warnings one guy went to brush a piece of swarf off the entrance to the hole just after he'd machine cut the threads.
It grabbed his finger and the thread wound on his finger all the way up to the knuckle. He was so shocked/confused, he didn't even hit the eStop. Luckily, he didn't loose his finger, but it made us all just a little bit more aware after that...
All the climbing, kiting, biking, DIY, Engineering I do (out of office hours) I get fed up with taking my wedding ring on and off (and then worrying about losing it). I've just stopped wearing it, even though it annoys the hell out of my missus. I might get a tat.