The great accomplishment of Jobs's life is how effectively he put his idiosyncrasies - his petulance, his narcissism, and his rudeness - in the service of perfection.
A lot of people change for good. Some people just fall off. Just trying to progress in anything, no matter what you're doing, I feel like any progression you make... some people aren't gonna be around you that were around you.
You have to have the service mentality in the sense that you subjugate your own ego, and you subjugate a large part of your own life to really helping other people, being successful on their behalf.
My writing model is my mother, who is a writer as well. She always valued clarity and simplicity above all else. If someone doesn't understand what you're writing, then everything else you do is superfluous. Irrelevant. If any thoughtful, curious reader finds what I do impenetrable, I've failed.
We sometimes think of being good at mathematics as an innate ability. You either have "it" or you don't. But to Schoenfeld, it's not so much ability as attitude. You master mathematics if you are willing to try.
That fundamentally undermines your ability to access the best part of your instincts. So my advice to those people would be stop thinking and introspecting so much and do a little more acting.