Not necessarily horrifying (maybe a horrifying waste of time), but a hilarious accident in Skyrim.
So I get sent up to the top of the mountain by the Graybeards to speak with Paarthurnax. I get to the top when over flies a dragon. Thanks to my all too quick reflexes when playing a game, I immediately attack him with my bow.
Cue a ridiculous half hour fight involving me bringing down his health, only for him to regain all of his health when it gets to a certain point.
I finally said "screw it" and reloaded my saved game. I decided to sneak when I got to the top, only for Paarthurnax to land and me realizing I'm supposed to talk to him
/facedesk