これはHarverd University CommencementでMark Zuckerbergが話したストーリーです。
「One of my favorite stories is when JFK went to go visit the NASA space center, and he saw a janitor holding a broom and he asked him what he was doing. And the janitor replied:“ Mr. President, I’m helping put a man on the moon”. Purpose is that feeling that you are a part of something bigger than yourself, that you are needed, and that you have something better ahead to work for. Purpose is what creates true happiness.」