A flaw in human psychology or perhaps a fundamental misunderstanding of our own psychology is the reason for unhappiness. If given the option, we would wrongly prefer to have more choice, more options, more money, when in fact being limited is the core predicament of happiness. Choice confuses our circuits, it causes doubt, it occupies our brain with endless analysis of all possible outcomes, and an ultimate discontent that we can't have everything. Of course, having everything would lead to more discontent for the same reason. Did you know that a year after the event, a parapalegiac and a lottery winner report the same level of happiness? Absurd, perhaps. But we assume that the intensity and longevity of our emotions, both good and bad ones, will be much higher than they are in reality.
I personally have been happiest when swamped with work, when I had to optimise my time and my efforts. Those were the times I worked hard and played hard, and I believe in some way, the best thing you can do to make yourself happy is to make yourself busy. The reverse leads to apathy. Working hard means that you have to play hard to counteract the work, and you have to work hard to earn the play. On a more superficial level, I was happy because I felt I was being productive, that what I did mattered (even if only a little), it made an impact, it was necessary. The explanation on a more psychological level stems from the setting and achieving of goals. Humans, proven, function very well when they have a day-to-day plan, when there are many but small goals in sight- a course work every week means that my brain is constantly occupied with simple, doable tasks. The reason why 5 year plans worked so well for Russia was because Stalin understood that. It worked so well because Stalin understood that a plan for the development of Russia in the next 50 years would have simply been inconceivable for the average person. Where do you start, even? Thanks to his understanding of this, Russia was able to compete in the Space Race at all in the 50's and 60's, and thanks to him, Russia is a world power even today, when, before his rule the country was absolutely destroyed.
What makes short-term goals such a positive reinforcement is that rewards are visible quickly, it's a Pavlovian scheme of operant conditioning that motivates us to achieve more and better next time... but on a small level. It extracts the best, it motivates and enhances, mostly because we feel that our work is rewarded and appreciated. Even more pivotal to the success of short-term goals is that we feel we have deserved this success. In the army, it is much more difficult to be promoted to a higher rank than it is in the air force. Yet, studies have shown that members of the military are considerably happier with their promotions, albeit much less often because the air force know that they have been promoted because somebody died, not because of their own merits. They don't feel that they have deserved it. They also get habituated to getting promoted and the frequency lowers their enjoyment and appreciation of the event.
I am secular but that does not prevent me from seeing that religion is simply a function of our human psychology. Ultimately, very subconsciously, even our predecessors whose brain was 1/3rd of our mass, understood that we need to be limited in order to prosper, both as individuals and as a collective. That is why they created religions and gods, because we can fear them, we can rely on them, we can pray to them, and finally, they give us a sense of perspective- there are things that gods can do that we are no capable of. Unfortunately, and it hurts me deeply, religion is pivotal to human success and happiness. This is the most developed that any of us have ever been, so much is available to us and we want more because now there are no limits to our dreams, supposedly. Yet we end up wishing for more power and more money, resulting in confusion on what to do with such disproportionate amounts of it; it leads to fear that we will lose our money and power, which in turn leads to aggression and/ or escapism- drugs, alcohol, shopping, entertaining TV shows with yet more competition.
What will happen? The most developed, those who are leading us into this towards the top of the ladder will collapse first. It will be a total annihilation, to the very core- the economy, their belief system, their social system. Has it not happened already with the Economic crisis? This crisis happened also in 1929 for the same reason- a success too rapid is unstable, it was too good to be true. I personally believe that, very much like a Pheonix, we will rise and rebuild our societies and ourselves. Stupidity was defined by Einstein as repeating the same action and expecting different results each time. Unfortunately, the human race is stupid. Fortunately, ignorance is bliss.