Costumes: Mirrors of the Soul?

Crypt Suzette is now available for pre-order and discounted at Barnes and Noble, Amazon, Target, and BAM. 

Does a costume disguise or reveal who you really are? That question comes up in Crypt Suzette, my sixth Five-Ingredient Mystery. When Val caters a Halloween party at Bayport’s bookshop, a costume contest is part of the festivities. The contestants are supposed to dress as fictional characters. When the prizewinner, Suzette, is murdered, her competitors are suspects. Val can't help wondering if they might have something in common with the violent characters they portray: Lady Macbeth, the Phantom of the Opera, Count Dracula, and Morgan le Fay, the evil sorceress from Camelot. 
 
Val, who dresses as Nancy Drew, tells her friend Bethany, “People choose costumes that mirror their personalities.” Do you agree? Or is wearing a costume an excuse to take on a totally different personality? How do you choose a costume?

Comment by July 21st for a chance to win an advanced reader edition of Crypt Suzette.
UPDATE: The contest is over. The winner is Gail. Thank you to those who wrote about the costumes they've worn and their reasons for choosing them. It was fun to read the variety of comments. The common thread is that we express ourselves through costumes whether they represent who we are or who we would like to be.