"Grit" aka mental toughness under duress.

I highly recommend looking into a GORUCK Challenge (https://www.goruck.com/the-challenge/) for anyone who wants to develop stronger mental muscle in a few short* hours.

It's amazing how just a short period of discomfort pares away the bullshit. You learn how to prioritize under duress, work with other people to assess, quantify and leverage strengths, and you figure out that you're capable of more than you thought.

You wouldn't think that a physical challenge translates outside of that scope. But it does, because most physical challenges are really mental challenges featuring a facade of physical discomfort.

*They will not feel short.