I've always loved Halloween. It must appeal to the fiction writer in me. On a regular basis I assume the guise of other people, so donning a costume just adds to the authenticity of it all. While the physical is disguise is enjoyable, and makes things easier, it's the character I really like. Being able to flesh out personalities makes the whole experience all the better. Being able to interact with others who are likewise engaged in assuming other guises makes the whole night a giant work of escape fiction, where pirates clash swords with Jedi. Where monsters dine with politicians and celebrities.
What could be cooler?