How does the story "A Horse and Two Goats" develop the idea of the need to interact with people who have vastly different identities from your own?

The characters of Muni and the unnamed American live very different lives, and their mutual areas of understanding are quite limited. Muni has not had the opportunity to travel abroad as the American is doing. He is very concerned with the pressing necessities if daily life but also wishes to live a life of of honesty and integrity. The American seems to love the superficial manifestations of Indian culture. He is attracted to the visual aspects of the horse—with an eye to displaying it as an object to invite his friends' envy.
As a wealthy man, the American seems capable of buying such an artifact and is unconcerned with its cultural or social significance. Muni is happy to think he has found a buyer for his goats. They strike a bargain that is, paradoxically, of mutual satisfaction, even though it is based on misunderstanding.
In many respects, however, Muni and the American are alike. Each is motivated by his own self interest, and neither one takes the trouble to find a solution to the language barrier. As an individual, each of them gains something he wants in the short term but neither is benefitting Indian society more generally. Muni seems to receive a greater initial benefit, as the money he gets will go a long way for his and his wife's expenses. But as a representative of his country and culture, he has lost more in functioning as an unwitting participation in the plundering of its cultural heritage.

"A Horse and Two Goats" is a story by Indian author R. K. Narayan. Its main focus is cultural insularity and miscommunication. Although some of the effect of this is comic, it also raises some serious points about the harm that such insularity does to both India and the colonial powers attempting to govern India and help India's development. 
Both Muni and the American do not know each others' languages and thus have difficulty understanding one another. Muni therefore thinks that the American is trying to buy his goats, while the American thinks that Muni is selling him the statue. If we look at the story more analytically, though, we find that it addresses more complex issues.
First, as Muni is a poor villager, as readers, we feel that he is justified in having little knowledge of American culture, but we also think that the American, who traveled to India, and is intent on bringing back souvenirs to show off his sophistication, should be more sensitive to Indian culture.
Also, we note very different traditions and value systems. Although Muni is a poor villager, he is very knowledgeable about the great Sanskrit epics that are at the center of Hindu religion. He is himself pious, and understands and explains the spiritual significance of the horse. The American, by contrast, appears crudely materialistic.
In the exchange, both seem unaware of each others' needs and values. Muni's misunderstanding of the American leads him to sell off, for a desultory sum, a crucial part of his cultural heritage. In terms of the American, we get the sense that the author is trying to explain that donations of aid in the form of cash will not transform the lives of poor villagers for the better, and that colonialism is actually culturally impoverishing as well as exploitative. 
This suggests that in a globalized culture and economy it benefits people in both developed and developing nations to understand each others' cultures better.