I'm going to wax a bit philosophical here, in contrast to my usual technocentric rants, so bear with me.
I was struck with a realization yesterday that the two traits that allow us humans to do such great things are the same traits that allow us to do such horrible things.
The first trait is the ability to sublimate our personal needs to that of a grater cause. This leads us to do such things as give up a comfortable life to travel to an undeveloped land and help the local people improve their condition; to fight against injustice in the face of personal attacks; to jump onto a grenade to save our comrades. We can identify with a cause larger than our own lives, and work towards furthering that cause at the expense of our own well-being.
But is also leads us to harm those who do not share our history; to pilot planes into buildings; to attempt to eliminate entire peoples because they are different. It is the adoption of an greater goal that removes our sense of kinship to the rest of humanity.
Conversely, the second trait is that selfishness that drives us to excel at collecting wealth that can be used to do great good. The billionaires that fund disease-eradication efforts, or publicize tragedies in far-off countries; the driven individuals that want to build rockets, or non-polluting cars - they expect to get rich from it, along the way.
But this leads to the seduction of power. Once one has enough money, one becomes accustomed to using that money to influence the rest of the world, and then that distorts the political process in the local governments - either directly through bribery and outright force, or via indirect means - funding 'policy groups' and industry councils that present an individual's view as a public opinion or social good. Soon any deviation of society from the personal preferences is decried as a bad thing.
So we must learn to walk the middle way, somehow, avoiding the extremes of selflessness and of selfishness, and tempering our personal view with that of society's.