This bias towards the extroverted can be daunting for those of us (often writers and editors, but also directors, actors and production designers) who are introverts. We've been taught by our schools, our society, and our business, that our natural instincts towards inner life and solitary contemplation are flaws to be overcome.
This is unfortunate. Some of our most creative individuals (think of filmmakers like Woody Allen, David Cronenberg, Todd Solond, Charlie Kaufman or Walter Murch) tend to be introverted.
Check out this TED talk by Susan Bain on "The Power of Introverts."