The process of Cultural Shock starts off right from the first days of your arrival to the foreign country you will be living in. During this period of time, known as the "Honeymoon", you will probably find the host culture rather interesting and appealing. After the first months comes the "Negotiation" phase, in which the differences between the local culture and your own start becoming evident. Very often in this phase all sorts of culturally awkward situations get triggered, some of which might get considered as culturally offensive or even senseless to you. In a few words, you might find yourself going through some mood swings that will probably make you feel that most people are rather annoying. Finally, the "Adjustment" phase is reached after 6 12 months of being in contact with the foreign culture and all its craziness. By now you have successfully developed the necessary tools to adapt to the alien culture, and most probably you have grown up a little inside.
However, Cultural Shock can be easily misunderstood with just "multicultural interaction", meaning you might be hanging out with guys from all over the world right now, without going through the process of transforming yourself by doing it. The difference lies in avoiding personal confrontation with an alien context by trying to keep in touch with a familiar environment, which will only keep you off from going out of your own cultural "bubble". While you might hang out in parties, classes, dinners, or trips with new friends from Brazil, Greece, Italy, Peru, China, Kenya, Germany, Russia, etc., this does not guarantee that you will experience real Cultural Shock. Most of the time, what one gets out of being caught in these routines without deep personal reflection, is just a narrow perception of others based on cultural stereotypes, which does not necessarily help developing cultural adaptation or personal growth. Getting to know yourself through an open personal confrontation with a whole new culture(s) is not the same than having friends with different cultural backgrounds.
It is true, Cultural Shock has its ugly side homesickness, excessive sleep, compulsive eating/drinking/weight gain, irritability, stereotyping host nationals, etc. but it also has its reward if you manage to go through its different phases properly. This reward might just come up once you get back to your home culture where, ironically, you might have a hard time re-adapting. Why would you have a hard time going back to what you already know? If you are lucky, because you have changed through this experience you are living today. In which phase are you in right now, is it the Honeymoon, the Negotiation, or the Adaptation? If you have not even started yet, then you have a train to catch, one that will take you to find out who you are and who you are to become.