Ah ok. The lesson I'm thinking of is in his first memoir, "Surely You're Joking Mr Feynman" in the chapter "The Dignified Professor" where he was feeling quite

Ah ok. The lesson I'm thinking of is in his first memoir, "Surely You're Joking Mr Feynman" in the chapter "The Dignified Professor" where he was feeling quite down because he believes he can't live up to the expectations people have of him. He makes a breakthrough in his thinking, when he realized that he's not responsible for other people's expectations. That's their mistake not his.