If you don't thing that dogs hate Halloween, take a good look at the poor guy in this picture:
Now I am not a hamster, that dog's expression says "This is one of the 4396508 reasons that I HATE halloween!". The poor guy looks for all the world like he'd rather be almost anywhere else in the world ... preferably either eating, sleeping, or getting to know the female next door.
I mean seriously, how would YOU like somebody anywhere from two to ten times your size to come along and dress you in ridiculous outfits and then take pictures? No wonder this guy looks depressed!