behold - the ten-point bulleted path to happiness:

• inherit a genetic propensity to happiness
  
• marriage
  
• make friends and value them
  
• desire less
  
• do someone a good turn
  
• have faith (religious or not)
  
• stop comparing your looks with others
  
• earn more money
  
• grow old gracefully
  
• don't worry if you're not a genius

assez simple, non?

Nigerians are the happiest people, and Romanians the unhappiest, apparently - according to this report from the New Scientist.
(I'll save the path to melancholy for another time)