“If we want a joyous life, we must think joyous thoughts. If we want a prosperous life, we must think prosperous thoughts. If we want a loving life, we must think loving thoughts. Whatever we send out mentally or verbally will come back to us in like form.”
Positive sum thinking is what grows the pie in a macro POV, but also in your own life. The more happy you are for others, the happier they’ll be for you.