The article concludes the finding this way:
Happiness and optimism are not just different, they can be contradictory. The Chinese are dissatisfied but upbeat; Europeans are happy now but dread tomorrow. Many links between happiness, income and optimism have yet to be teased out. This new data—though not the last word on the subject—should help.The search for happiness is not new phenomena. Remember, In 1776 the American Declaration of Independence argued for “certain inalienable Rights, that among these are Life, Liberty and the Pursuit of Happiness”. I wish more countries will take on this subject more seriously.