It originally comes from All Hallows eve (if you want to know more of the origin I can oblige. I would say that in England ( I can't speak for the rest of the isles) we didn't really celebrate it as much as we did acknowledge it you might have a party but only recently has the American tradition of trick and treat has become normal. Although for me this was discouraged as my mum was a believer in the pagan an considered the modern interpretation disrespectful, though we often had a gathering and a tarot reading.