This was written during my mid-term exam in Cultural Geography, a class I took at Chesapeake College for fun last year. The question was: "Which issue is the most important one in human life, out of the ones we've discussed this semester?"
Though an argument can be made for all of the issues we've covered thus far, ultimately all of those issues fall back on one single issue: ethnocentricity. This is the most important problem in human life, as it influences and, in some cases, directly causes the other problems. Ethnocentricity is the belief that the normative way of life of a particular culture is inherently better than the normative way of life of any other culture. This belief can morph into believing other cultures are wrong, evil, or dangerous, but even in its more benign form, this belief is inherently dangerous.
Before discussing the danger, let's discuss the benefits and necessity of ethnocentricity. Each person is born into and grows up in a particular culture, or mix of cultures if the family has members from different cultures. To learn how to fit in with this particular culture, the person learns what is normal and what is not. When the person behaves in a way that is not normal, that person is punished, either directly by authority figures (parents, teachers, etc.) or indirectly by social consequences (ostracism, teasing, physical assault, etc.). The consequences of behaving according to that culture's norms are good; the consequences of not behaving according to that culture's norms are bad. Thus, the association is often made that the norms of this culture are good, while behavior that is not normal is bad. This is a necessary consequence of belonging to human society and is not, in and of itself, a bad thing.
The danger comes when one projects one's cultural norms onto those who are not part of the same culture. This can result in actions that are meant either to improve the lives of those "unfortunate" people who do not have the same culture, or to correct the "wrongs/evils" done by those outside of one's particular cultural group. Even in the more benign form of wanting to help others, this can result in harm. To believe one is capable of helping another means that one believes he or she fully understands the situation (not used in the geographical sense here) that the other person is in. Often this assumption is made out of ignorance of the complexity of the other person's culture.
An example of this more benign danger of ethnocentricity is when a country, such as the US, interferes diplomatically with another country's affairs without fully understanding that other country's culture (nevermind history, politics, or economic situation). Darfur would be an example of this, assuming Professor Crouse is correct in that it's not a racial or religious war but one caused by the lessening of natural resources from the growth of the Sahara. If this is true and the US interferes diplomatically under false assumptions, because we are the US and we know better than anyone else, this could exacerbate the conflict instead of ending it.
The more dangerous form of ethnocentricity has led to numerous conflicts throughout history all over the globe. Any time genocide occurred, ethnocentricity, usually cloaked with economic or patriotic excuses, has been the root cause. Any time war has been waged under false pretenses, ethnocentricity has played a part in the decision, often cloaked by economic, patriotic, or national security excuses (Iraq). Any time a religion is spread throughout the world by force or under the assumption that it is the only Right Religion, ethnocentricity hides underneath the holy garb (Crusades, colonization).
At least indirectly, ethnocentricity also causes the problems of primary product production (capitalism is assumed to be the best economic system because it happens to be our own), migration (when ethnocentricity is not the direct cause, it adds to fear of migrants), population maintenance (it's not just about these people not having money for food, but also about those people not mattering as much as "our own"), language extinction... Every human problem we face today is affected by ethnocentricity, whether it is directly caused by it, or whether it causes inaction, apathy, or fear.