Not a fan of costumes because of how hot I get. My body runs really really warm and pretty much every costume I've worn has given me some kind of temperature related problem that spoiled peoples' good times. Maybe I should dress as something slutty and revealing so that won't happen again. :P
Ahem, anyway... I do love the decorations, themes and colors, the fall food, the candy, and the booze if there's any involved. Seeing the little ones in their costumes always puts some cheer into my eyes, too.
Mostly, I'm in it for my kid. :D This will be his first trick-or-treat since he was too little to fully appreciate it last year.