According to Dr Elayne Kahn your Halloween costume reveals alot about ones personality:

Witches -- Enchanting people, take control in romantic situations. Always honest about there feelings.
Politicians -- Suspicious of authority. Judge people by there actions, not by their words. Opinionated.
Movie Stars -- Concerned about reputation, success. Enjoy being the center of attention. Socially active.
Clowns -- Sensitive to others emotions, self-assured, can laugh at themselves.
Aliens -- Often have a hard time understanding people's intentions.
Monsters -- Appear calm, but they're hiding internal turmoil. Have difficulty expressing themselves.
No Costume -- You're afraid af criticism. Uptight, you have a hard time letting go. Underneath it all, you have an intense need to be accepted.