Questions of personality have vexed mankind from the dawn of personhood: can people change? How do others perceive me? What is the difference between normal and pathological behavior? One's personality is so pervasive and all-important that it presents a clinical paradox of sorts: it is hard to assess our own personality, and impossible to overlook that of others.
Extroverts make up about three-quarters of the American population, and as such come in all stripes. They zip through the world in search of novel experiences, social connections and leadership opportunities. Extroversion is a core factor of personality and is difficult to modify.