I'm a big fan of Dennis Prager. Dennis is a brilliant conservative talk show host on the Salem Radio Network.
Dennis authored an article discussing happiness as a moral obligation - on a large scale and on a one to one scale. The concept is genius. If you force yourself to be happy in order to affect the people around you, it becomes a very nice circle of good emotions. Think about it... you make your spouse happy by being happy and it becomes more and more easy for you to be happy.
Read the article here.
You should watch this. It will change you in very good ways.