Happiness is a state of mind that can only be defined by the thinker in question. In other words everyone has a certain amount of actual needs that in turn require a certain amount of money to take care of. If we are using money as a counter I think I would be very happy if my home brought an estimated 75 big ones in annually. Why people don't always get happier in relation to the amount of money they bring in is often due to the fact that the more some folks make the more bills they acrue. Stupidly the more money they have the more they place themselves in debt. It piles up and up as they try to keep up with the jones' and although they make way more money than the average citizen they struggle to survive.
How does a poor monkey like me know this? I have friends. One friend I knew had a great career and between he and his wife they could have lived comfortably and peacefully but instead they had to have more, and then more, and then more, until they had so much they couldn't keep up with everything. Dude makes so much more money than I will ever see unless I get lucky and get published or win a lottery and yet you could look at us and see that i am way happier and more stress free than he. They did it to themselves, overextending and then complaining when they get taxed like nobody's business. If people would stop being such high octane consumers and grow the hell up and act like responsible Americans they wouldn't end up with all this debt and stress.
Ignorance is bliss, being unable to afford anything other than your immediate concerns, while often depressing, is also a relative bliss.