Our granddaughter and grandsons adore the Elf on the Shelf fantasy.  Their moms take quite a lot of energy and imagination to place the elves in different positions and with different accessories each day prior to Christmas.  The storybook is engaging.  However, I'm not quite sure whether they truly believe that the elf is "watching" them each day.  Yet, they enjoy the daily event of finding their elf.  It has become a sweet memory of childhood.