Stillness Is the Key by Ryan Holiday

How much better would the world be with more of this behavior?
How much better would your own life be?
Kennedy, like Lincoln, was not born with this stillness. He was a
defiant troublemaker in high school, a dilettante for most of college
and even as a senator. He had his demons and he made plenty of
mistakes. But with hard work—work you are capable of doing too—
he overcame those shortcomings and developed the equanimity that
served him so well over those terrifying thirteen days. It was work in
just a few categories that nearly everyone else neglects.
Which is where we will now turn our focus—toward mastering
what we will call in this section “the domain of the mind”—because
everything we do depends on getting that right.