Celebration of the Eve of all Hallows, or Samhein(sp) is not devil worship.
It originally was a celebration in honour of our deceased ancestors, still practiced as such in Latin American countries as the Dia del Muerto - Day of the Dead. More joyous and less solomn than Memorial Day here.
Catholocism, in it's way of adapting existing holidays into "christian" holidays, named Nov 1 All Saints Day to help with it's conversion of the pagans.
I've played the "role" at parties (witch or vampire or whatever), I've given out candy, I've had a private ancestor dinner where I set places at the tables for each ancestor I wish to honour and make foods they liked. I was the only human there.
As with most of our holidays, the American Corporations have capitalized on them with the ghosties and faeries and costumes and candy and parties.
Party on
Brenda