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. :-(
It's always worth 15 seconds of time to find and put on the safety glasses for a lifetime of having both working eyes. I'd ruminate over "if I had just found my safety glasses" for the rest of my life if something flew off what I was working on and destroyed one of my eyes.
Same with ear protection. It's not worth being deaf (or even partially deaf) to get a job done 15 seconds faster.
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.
I had an angle grinder disc shatter on me and one piece took a huge gouge out of a wooden toolbox I had built. I am afraid of angle grinders now.