Happy at work?

"Don't over commit yourself or your team."

Sadly, as a developer, I usually have people doing this for me.

"Don't waste precious energy on malice and gossip."

The problem is that in many offices, politics matter. If you don't play the game, you will end up getting passed over for raises, etc.

"Never obsess over things you cannot control."

Most of the time, I am forced to obsess about it because upper management decides me to put me in impossible situations.