"...it put the gravel in your gut and the spit in your eye."

Angela Lee Duckworth has just returned from her 25th class reunion at Harvard. “People’s lives really do turn out differently,” she observes during an interview in a stylish boardroom. “And it certainly can’t be explained by how intelligent you remember them being when they were sitting next to you in organic chemistry class. Some of it is luck, some of it opportunity.” And some of it is “grit,” as Ms. Duckworth has told the world in articles, lectures and a 2016 bestselling book, “Grit: The Power of Passion and Perseverance.”
https://www.wsj.com/articles/is-there-anything-grit-cant-do-1498254238

What do you suppose teaches grit?