Wow. That description of the Seahawks milieu says to me that it's not developing traits like grit and optimism, but rather selecting for them. I wonder if intervention studies for this sort of thing ought to be done with intention-to-treat analysis, just like with drug studies [1].
https://www.psychologytoday.com/blog/rabble-rouser/201512/is...
And what's more, this "grit" trait, the propensity to follow through and get stuff done, appears to be a set of inherited traits as well.
https://www.newyorker.com/culture/culture-desk/the-limits-of...