I lost four spokes on my morning commute when the chain decided to jump off the big cog. Of course I don't have a spoke protector. (Who needs a dork disc? Bad things won't happen if you keep your bike maintained. /s) I was lucky to skid to a stop rather than crash when the rear wheel locked up.
I love the satisfaction when something goes wrong on a ride and you're prepared for it. I came off my bike a few months ago and scraped up my elbow pretty bad. Despite the mild concussion I remember being quite excited to be able to patch myself up in the field, hahaha.