I have an old book, Humanity and Happiness, which was written by a Norwegian during the Nazi occupation, hidden, and published after the war. The author maintains that the Norwegians were never happier than when they were united in striving toward a common cause - surviving the occupation. He postulates that humans must strive, have reason to strive in order to be happy.

The corollary to this is the comment made to me by then president of Antioch College, Arthur Morgan, as we walked across campus (1957): that the highest incidence of suicide was appearing in those countries with the most socialism because people no longer needed to strive.

There is a line, different for each individual and, perhaps, each society/culture, between life being too stressful and having nothing, or insufficient, to strive towards.