I believe that the best way to describe the impact of having gone abroad would be to present it in the form of advice to those who have yet to do the same:
Spending a year abroad does not open your eyes merely to the tones of another civilization, but inwards into the core of your persona as well. The moment you step off that plane and set foot on foreign soil, that is when it all becomes real. Fantasies, hopes, and expectations are swept away by the reality of the situation to which you have voluntarily exposed yourself, and the challenge of prospering in such a place becomes rapidly apparent over the next hour, the next day, and so forth.
Overcoming logistics, cultural unknowns, and the terror of interacting with native people as one who does not fundamentally belong is enough to survive for a year. But the fruits of an experience abroad come from raising the courage to overcome one’s own sense of fear and pride; to be ready to make mistakes, and to learn to withstand embarrassment. It is these personal thresholds that you must cross to be able to even begin experiencing the alien environment surrounding you. Without having come this far, one’s experience in another country can hardly extend beyond the imagination inspired by a marriage of textbook trivia and popular stereotyping.
One way or another, a year abroad will reveal new information, and while the breadth of that knowledge will certainly be greater should one learn to take initiative in exploring it, the real opportunity in traveling abroad lies in the opening of one’s senses to distant worlds, unfamiliar peoples, and new ideas. Once you have gained that, then it will be easy to enjoy the rest of the year. More importantly, the confidence you will have gained will last beyond the day you step on the plane headed back home, and you will be stronger for it anywhere in days to come.