There's a lot to love about America - freedom, the melting pot of diversity, individualism - all attractive concepts, especially to an introvert. In fact, the introverts were probably the first to feel crowded in England and to daydream about all the space they would find in the New World. Peace! Quiet!
America is a noisy culture, unlike, say, Finland, which values silence. Individualism, dominant in the U.S. and Germany, promotes the direct, fast-paced style of communication associated with extraversion. Collectivistic societies, such as those in East Asia, value privacy and restraint, qualities more characteristic of introverts.
Often confused with shyness, introversion does not imply social reticence or discomfort. Rather than being averse to social engagement, introverts become overwhelmed by too much of it, which explains why the introvert is ready to leave a party after an hour and the extravert gains steam as the night goes on.