Also the humble rotary (Dremel style) tool. I was doing some work with mine yesterday and - in a moment of complacency - actually had the tool bit make contact with the surface I was working on for a second or two before I realized "shit, I'm not wearing safety glasses." I shut it down and grabbed my safety glasses pronto. I'm not exactly a "safety nazi" on this stuff, but some things just make too much sense to not do. And even a rotary tool can send shards slamming into your eyes or something that could cost you your vision. :-(

A buddy has a wood shop and one time after a router spun down, one of the bits had gone missing. Undoubtedly lodged in a wood roofing element somewhere, but at least it did not go thru anyone.

Absolutely! I snapped a router bit off by being a bit too aggressive in the engineering shop at university. I'm still thankful it didn't injure any of the several other people in the room; it could have been very damaging coming off at a different angle.