To join in on what Matt and Martin are saying:.. Hypothermia and MY mental state almost killed me on a back country hunt in Idaho. I was alone on a deer blind, having been left there by my guide (who I now call "lost Louie".. because he was always lost). The guide instructed me to just wait for him to come back for me (with the horses) for the ride back to camp.
The temperature dropped from +35F to about -25F in the space of an hour, and it started snowing. I had only a vague idea of where camp was (my bad!) and (the almost fatal Mental State Issue) I didn't want to look like a timid greenhorn by forting up and starting a fire. After all, I was properly clothed.
By the time I realized how cold I was... and that it wasn't going to get any warmer any time soon.. my hands were shaking too much to light a fire. I was saved by two Snickers candy bars, which I ate.. ran around in circles until I (briefly) warmed up enough to use my hands, then started the fire.
I later learned that Louis was watching me from another ridge. Wondering why I didn't start a fire like he had. Wondering why I was dancing around.

I've concluded that, for me, not wanting to look timid or overly cautious to others is a potentially fatal Mental Flaw which can lead me to endure what I should correct. So now I let my outdoors buddies know that I'm the designated Coward! They can be the cowboy adventurers. I'll hunker down, get warm, and stay sheltered.