Sinek says he wouldn’t have been inspired to do any of those things if it weren’t for books. There are two in particular that he calls life-changing: “Man’s Search for Meaning” by Viktor Frankl and “Finite and Infinite Games” by James Carse.
From “Man’s Search for Meaning” by Viktor Frankl:
We cannot control the world around us, but we can control our attitude. Whether a situation is good or bad simply depends on how we see it.
I learned I can control how I feel regardless of what happens around me. I can choose to be positive. And the best part is, with a new positive mindset, I was able to find all the evidence around me to reinforce that I was on the right path.