One clue to how to achieve happiness comes from one of the 20th Century’s great minds.  Albert Einstein shared his personal theory of happiness in a short handwritten note.   In 1921, Albert Einstein was on a lecture tour of Japan when he was delivered a message by a local courier. For reasons not entirely clear, he tipped the courier not in cash, but in short notes that seemingly contain Einstein’s advice on how to live a happy life.

Einstein's note.

The note, signed and dated on stationery from the Imperial Hotel in Tokyo in 1922, read, “A calm and modest life brings more happiness than the pursuit of success combined with constant restlessness,” in the physicist’s native German.