The reason we go door to door saying "Trick or Treat" and asking for candy is, on October 31, the Irish lit bonfires to scare off wandering ghosts and held a feast in honor of the Lord of the Dead. They went door to door seeking food and wood for a festival. Donors received their blessing while misers were given a curse.
According to superstition, you will see your future spouse over your left shoulder in the mirror at midnight on Halloween.
Did you ever wonder why we wear masks and costumes on Halloween. The ancient Celts thought that witches and ghosts roamed the countrside on the night of October 31. In order to frieghten and confuse then, they wore masks and costumes while walking outside at night.