What would you call someone who easily gets mad over little things and feels that he is better than others?

Impossible to say. Many possibilities exist with someone who responds this way -- all the way from personality characteristic to psychopathology. Possibilities include alcoholics -- who often act as if normal rules don't apply to them, & are critical of others too. Hypomania; narcissistic, borderline, antisocial character disorders; general perfectionism, compulsiveness; some anxiety disorders; list goes on.