My theory:
We are empty and miserable. We are led to believe that the more we have, the happier we will be, but that's not the case. Learning that is frustrating. We have no real role models. The ones we are provided are phony and either solve their problems with guns - legally or illegally - or they don't have "real" problems at all. As a society, we do not promote working through problems by facing the actual issue. We hold everyone else accountable for our "problems". When we don't have problems, we create them. We're a miserable lot that revels in and celebrates it. Just look at all these reality shows - these are the most unhappy, miserable, ungrateful, self loathing people on the planet - AND WE PAY THEM TO BE SO! And when we find someone that's not pissed off and miserable, we belittle them and blame them for our problems. We feel guilt for the things we have because deep down we know the cost, but don't want to admit to it - it's easier to blame "them over there" - and this guilt leads us to being ungrateful and unable to enjoy the things we have, which leads to frustration, anger, violence and denial. If we only had a few more dollars to play with, we could all get therapists....hey, let's LOWER TAXES!
I dunno. I'm a pretty happy person.