People are roughly divided into two categories – extrovert and introvert.
Most of us are in the middle, or depends on situations. Take myself as an example, I enjoy hanging out with people and not afraid of talking to passengers on the street. When I did man-on-the-street interviews for product development, I felt more excited than scared. However, I do need the time I spend with myself or talk deeply with close friends, which make me peaceful. Also, if I have to choose, I prefer the latter.
I believed many people have already watched Susan Cain’s speed ‘The power of introverts’ on TED.