I've long had the idea that evolution has adapted us for hard living - hunting down our food and running from hungry lions. When things get too good and we have nice lives we are miserable because we aren't genetically equipped to deal with this much prosperity (speaking in the general "we" meaning humans, there will always be exceptions). I've long been amazed that here in America, as life gets better our society seems to get crazier and crazier and so many people are unhappy and stressed.
Fortunately, over the next hundred years we are going to change human beings and make us much smarter, via genetic manipulation, smart drugs, super computer teaching techniques, nanobots in the brain or maybe all the above and a couple others I haven't thought of.
Then it will be a whole new ball game. Imagine a society where we have Replicators in our homes (the Star Trek kind, not the Stargate kind) and can order up any food or device we can think of so there is no want of any kind, no need to work or steal, and the average IQ is 200. We will either destroy ourselves or do some really amazing stuff, like break the speed of light and start flying around the galaxy