The arrival of many people in our life is usually initiated by a change of location, say, going off to college. The better the college, greater is the diversity in the students. You meet people from different regions of your country. You like their behavioral contrast and similarities with yourself. Sometimes you argue with them about the greatness of your own culture against theirs. Other times you wonder about the greener grass on the other side. What I believe to be most important aspect of such a situation is the learning.
The things that are present in other cultures and absent in your culture provide an easy and great way of imagining how life could be better in your own culture, for you and others. Better education system, better lifestyle and a better social circle usually come from learning the ways of others. Time is the most expensive resource I have found in my experience. What took thousands of years in making can now be spread and learnt in far lesser time. The exchange of intellect and knowledge is what drives mankind advancements in a faster and a more efficient way. But when two identities meet, one more possibility arises, war.
If exchange of ideas is what drives the humankind forward, war is what drags it backwards. Resources spent in driving the adversaries into extinction are a lot higher than it should be. If all of these resources are used properly, calculations show that global poverty can be exterminated twice. War happens usually when one identity feels threatened by the other or it wants something the other has. But there is something more basic to war, simply put, conflict of ideas. The conflict can be as simple as authority over resources at a certain location or as complex as right to live or right to freedom. And what is the purpose of war? To kill one of the ideas.