"I freely admit to being a bit of a masochist when it comes to physical activity and pushing myself to extremes. As such, knowing when enough is enough, and it's time to bail, is all that much more important."
+1 But devilishly hard to keep in mind when you're really out on the edge, often until it's too late. You did an excellent of explaining that dynamic in your write up. I hope this one gets widely read.