"Not every library job entails direct customer service. But no matter your title, chances are you’ll be spending at least part of each week with the public. Does this mean every librarian is an extrovert? Hardly. Most of us are still introverts, me included; we’ve just developed the skills that allow us to meet and greet with the best of them. See Susan Cain’s Quiet: The Power of Introverts in a World That Can’t Stop Talking for tips."