What follows is a quite cynical perspective of humanity.
So three things in general:
1. We instinctively seek order and harmony in disorder and chaos, even if those patterns do not actually exist. But we subconsciously do this as a way to make sense of the world around us; essentially we want to believe that things can be simplified and assorted into neat little packages. We try to find patterns of order and harmony in nature or otherwise chaotic scenarios, even if those patterns only exist in our heads. We do this as a way to make sense of our surroundings, because we are inherently afraid of chaos and things that we do not understand.
2. We are afraid of failure more than we are happy about success. Just like how pleasure can be seen as being the absence of pain, success can be seen as being the absence of failure, and harmony can be seen as being the absence of disorder. But without having ever experienced pain, we cannot effectively appreciate pleasure; without having been through failure, we cannot appreciate success. We have inevitably seen true chaos and true disorder and, to avoid that hell or to avoid being afraid of the unknown or things we cannot fathom, we instinctively seek order in every situation.
When humans make progress, they do so because they fear the prospect of failure more than the resulting feelings associated with success. Because happiness is fleeting and further challenges inevitably await.
3. We are constantly fighting our animalistic urges of destruction. Humanity is, by its very nature, a destructive force. It is much easier and more convenient for us to destroy than to create. Effectively there are institutions in place, such as justice systems and social conventions, that dissuade us from destructive activities. At the same time we are rewarded for pursuing constructive projects. But the very fact that such social rules and pressures exist makes the convincing argument that we must fight the desire to destroy by artificial measures and social conventions. Again, we are afraid of destruction and we applaud construction.
But we cannot deny that there is a dark side to people. We do things not necessarily for ourselves but in an effort to "fit into" society and have a comfortable life not only within the confines of our own imagination but the world and people around us that we can relate to at large. We don't want to die because we are afraid of the pain that we associate with it, we are afraid of what might happen to us after death (the unknown part), and we fear what our demise might mean to people who love and care about us. So, in effect, we create because we have been told by society to do so, we succeed because we have become convinced that success is preferable to failure. But at the end of the day, even if you might be a success with many constructive credits to your name, you might feel a certain emptiness inside -- an emptiness that results from the stifling of the destructive power inside of you.
There is a saying along the lines of "boredom is a breeding grounds for evil". Boredom by itself is neutral and impartial; however, it is the very nature of the human mind that resorts to the negative impulses and the worst case scenarios when the mind is seemingly "empty" and devoid of any thought, positive or negative. Paradoxically, we seek order and harmony in chaos and disorder but, in moments of boredom, we fall back on the animalistic tendencies of destruction, chaos, and disorder. We are afraid of things we cannot understand and cannot ascertain patterns in, and yet we are utterly fascinated by them.