I've had my share of unfortunate failures in recent years. My boxed set follows.
Campy Hi-Low failure; don't know if the spoke broke first, causing the flange to crack, or vice versa. Either way, instant retirement:
I did this one mile into a 30-mile ride when my rear wheel momentarily locked up (long story). Didn't realize the extent of the damage until arriving home:
Spoke nipple failure, just hours after completing a gravel ride to the Snoqaulmie Pass Tunnel on the Iron Horse Trail:
Aw, man - almost NOS:
Borked 14T Regina cog:
Snapped the nose portion of the shell about 3/4 of the way across. Instant retirement:
Regina freewheel inner body sheared off while in use. Only failure like this I've ever had - or seen, for that matter. Lucky I was within a mile of home!
Most recently, the nose anchor on a Flite Evolution failed after taking an exceptionally hard bump while I was "on the rivet":
Since these are massively expensive on Ebay (I'd even say overpriced, and I own one), I gave it a go at fixing. Amazingly enough, my repair has held:
DD