[quote=@Legend]
Here's my insight: Human beings have a natural tendency to be in control, whether it be of themselves, others, "fate," etc. This is evident through claustrophobia, leadership, and the fear of the unknown. The latter is especially important because it holds many implications; we know it to be true because knowledge allows us to gain greater control, and if we have no knowledge, we have absolutely no control over our situations and futures, particularly because we can't plan accordingly. This leads to submission throughout the world, and a desire to be controlled by some, because they desire a leader who does know, because that is less risky and allows them to be in more control than attempting to do so themselves. Because of this desire for control over others, humans have to find a way to force this to occur. This cannot happen from an intellectual standpoint because they cannot guarantee the other will comply or even agree (considering the average intelligence of a human), adding yet another variable beyond their grasp. However, there is one concept that prevents a human from being able to escape the control of another: death. Therefore, humans fight and are drawn toward fighting because it allows them to express both their own strength, limiting defiance, but the better fighter they are, the more likely it is that they are able to inflict death upon their enemies, and control those who stand in their way.
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I like it. And it stems from pride, too. A very clever teacher of mine once said that all sins, and even many negative emotions all stem from pride as a source.