This little nugget of wisdom stuck with me as I noticed the parallels to traveling, and the problems the world faces today. We are all the same people, we share the same DNA, we all have hopes and dreams. Each different culture brings their own unique take on life. But physical separation and "tribal" differences have put up barriers between us. Tribes rally around their flags and fight for reasons that may not have merit. The saddest example of this is the genocide in Rwanda, where people identified with either Hutu and Tutsi tribes. Archaeological evidence shows that the two tribes shared the same language, culture, food, and even intermarried. But the two tribes, with so much in common, instead fixated on the very small differences. This is captured eloquently in a paper by Kolsto, and goes back to Freud's idea of the Narcissism of Little Differences, which has been gaining favor again recently.
To quote from Wikipedia, " ... in a loving relationship there can be a need to find, and even exaggerate, differences in order to preserve a feeling of separateness and self." The newer theories are that this simple idea is exaggerated many-fold when it comes to tribes and countries, until two groups who are very similar end up at war.
We will never all gain the wisdom of Iroh, but as a traveler I try to keep his little nuggets in my mind as I come across new cultures.