[She gives him a flat, almost offended look, but it quickly fades into something more resembling exasperation.]

Yes, there certainly is. It's the day where the bonds between the world of spirits and the world of the living are at their weakest. Ghosts and demons wander the land, and things outside normal human knowledge are commonplace. The feast of All Hallow's Eve is meant to honor and placate these otherworldly beings. It's a tribute, and a celebration of something we don't fully understand.