No one can truly pinpoint an American culture. The differences between geography, demographics, and natural resources is quite stark. Similarities may be found in clusters, but for the most part-the further one travels, the more cultural worlds diverge. Despite being citizens of the same country, wandering too far from the region of origin gives one the feeling of being a stranger in a strange land, thus creating a culture clash.
Personality, culture, and experience vary from place to place. These facets unite people in clusters, yet ensconce them from outsiders. When an outsider wanders into a different culture-the natives might as well be aliens; for that is how the natives perceive the outsider. Personality, culture, and experience serve as the building blocks for culture, and culture is a defining characteristic of a region.
Barriers are not always physical constructs. A closed mind can block the outside world to new concepts more effectively than a physical wall. If one were to break through a mental wall, they might find commonalities with a stranger, but only if one is willing to seek commonalities. However, breaking down cultural barriers is usually difficult, especially when fear is present.
Cultural factions are comfortable because of the sense of inclusion it provides. Reinforcing preconceived notions feels great, but it stagnates the mind and soul. Staying in the usual comfort zone is an cultural dead end. There are various forces at work that keep people from uniting, and those forces prevents the advancement of culture.