Most people think of Halloween as a commercial holiday, strictly in place for kids to get free candy. In fact, it is an offshoot of All Hallow's Eve, the day when the veil between the worlds of the living and the dead are at their thinnest. Jack O' Lanterns were originally used to ward off evil spirits, while the sweets were used to ply a dead loved one. Costumes were worn to confuse the spirits so they would not cart off the living.
I highly recommend that everyone research the roots of this colorful holiday. Have a safe and Happy Halloween. Blessed Be.