As far as I can tell, everyone experiences culture shock during their first international experience - as a student, an educator or some other trade. The very definition of culture is what is important to the people in a specific society - their values regarding "arts, letters, manners, scholarly pursuits, etc." as according to Dictionary.com. In today's globalized world, countries are fairly aware of each other, so everyone has at least read about other cultures. Secondhand book knowledge, however, is nothing compared to being immersed in the personal experience.
There's nothing like realizing that the values we are raised on become very internalized and ingrained, whether we agree with them or not once we actually think about them. When the children I teach and the teachers around me disagree with my methods or ways of thinking, this becomes very obvious. In America, I often felt somewhat un-American due to my Communist Chinese upbringing thanks to my immigrant mother. When I was nine years old and she took me traveling to Hong Kong, the people there had commented on my American accent and "over expressiveness".
Out here, in one of the most beautiful and as yet natural (read undeveloped) suburbs of South Korea, I often think about the chemistry of my dual identity. Different skin tones and colors are a given in America because everyone's parents were immigrants at one time or another. Foreigners here either come to teach English or are manual laborers. The only place where no one seems to bat an eye at you for speaking a foreign language or dressing differently is in Itaewon, a neighborhood in Seoul. My friends and I sometimes comment - as fellow Americans - that Americans have the need to differentiate themselves so much that there are fierce regional loyalties and separate atmospheres for different states. Here, if you ask someone whether they are Korean and they turn out to be, they would be wondering if you are insulting them because their national pride is so complete.
There is a reason for this. South Korea had been alternately invaded by Japan, North Korea, and even the Chinese at one point. They need their unity to survive as a country - just as the U.S.A. was never more united as when the Twin Towers were just attacked. While the U.S. and South Korea function very differently as countries - except for capitalism - they are still allies. For business. For democracy.
On a personal basis, I still have not been able to be comfortable in this hierarchy, which feels almost feudal to me. While people are allowed to question their superiors, they must watch their tone of voice very carefully when doing so. American culture is based on questioning authority and rebelling, but these acts are not considered to be acts of disrespect. They are almost encouraged half the time, for the sake of people making their own choices and doing their best to practice critical thinking. Individualism is not an ideology here. Being alone is an indication that the person is losing at her social game, because she is being outcast. I remember the loner figure having an odd sort of glamor to him in American culture from reading "Shane".
Still, I had also resolved not to judge the people surrounding me by American standards, because that is not what they grew up in - and in fact, it's not even something they hear about aside from the advertisements for fashion from Europe. From these commercials, I think they think they know what American and European standards are, but these ideas are probably not accurate at all. Same for the feedback from American media. Anyhow, after my body mostly recovered and I wasn't consistently tired after a month of being here, I thought the culture shock was over. Psychologically, however, I'm not sure there is ever actually a cut off. I just have to find a middle ground where I let myself be, and let them be as well, I guess.