Fear is a vital response to physical and emotional danger—if we didn't feel it, we couldn't protect ourselves from legitimate threats. But often we fear situations that are far from life-or-death, and thus hang back for no good reason. Traumas or bad experiences can trigger a fear response within us that is hard to quell.
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.