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.
Boldness doesn't mean rude, obnoxious, loud, or disrespectful. Being bold is being firm, sure, confident, fearless, daring, strong, resilient, and not easily intimidated. It means you're willing to go where you've never been, willing to try what you've never tried, and willing to trust what you've never trusted. Boldness is quiet, not noisy.