There are so many reasons people do not get along. Human nature is what we have in common but the variables in life give us all different perspectives and thought contexts. When a person or members of a group believe that their perspective (or wants, needs, goals, etc.) is to come first always, conflict will follow. I do not think that understanding another's perspective, culture, religious views, wants, needs, goals will stop conflict.  It may contribute to the overall resolution.  But the basic problem is an inability to care about others and the territoriality that results from the hunger for power and money.  It will take much longer on the evolution chain and considerable spiritual growth before human selfishness and greed are conquered. The solution?  Teach and model in one's own circle of influence, no matter how small, the virtues of tolerance, nonviolence, personal control, compassion, and all the other peacemaking ways of being. Such modelling is the pebble in the pond.