Can't remember details, so no particularly interesting story around it I guess. Just a couple of times when something had broken at an unknown point in time and I needed to figure out which commit. I've been using git almost since its inception, and in a work setting since maybe 2010. And in that time, I've used git-bisect maybe ten times. While that might make it sound like a useless feature, it is a life saver when you do need it.