On this day last year, I was writing to myself about my shitty summer of 2017.

I was living at The View on Temple University campus, interning and making $10 an hour.

I was smoking weed with a girl interning at a bank making $30 an hour.

I envied this girl in private, but I was wary not to let my envy influence my interactions with her. After all, I needed a friend to smoke with.

Later in life I discovered Charlie Munger, vice chairman of Berkshire Hathaway, and his Almanack.

He writes “Beware of Envy,” that which the world is driven by.

Warren Buffett agrees, Envy is a silly sin with no upside.

Envy exists everywhere humans exist: classrooms, boardrooms, hospitals, banks, startups.

If you are a leader in any of these places, you must be wary of envy. Even if you feel envy, as a leader it is important not to let it drive you into pessimism.

As Bob Iger notes in his autobiography The Ride of a Lifetime, ““Even in the face of difficult choices and less than ideal outcomes, an optimistic leader does not yield to pessimism.”

THE TAKEAWAY: Become an optimistic leader.