I can't tell you how irritated I get around Halloween time (if I offend anyone during this post, I apologize in advance, just sayin). I can't tell you how many parents I hear say "It's the devil's holiday, my kid won't be trick or treating". Really? So your kids dressing up like Spiderman and Barbie then going from door to door begging for teeth rotting candy is all just a front for devil worship?
Halloween originated as a Druid/Celtic/Irish practice called Samhain. The beginning of their year was the 1 of November, so they celebrated Samhain on the night of October 31. That was the night that they believed spirits came back to mingle with their people. The Celtic people would wear masks (which is why we have present day costumes) to either mingle with the good spirits or scare the bad ones away (they were also trying to disguise themselves so as not to be mistaken for human). The fact that those spirits "came around" helped the Priests of that day to make predictions for the coming year. Masks and costumes were also used to tell stories around the giant bonfires that were lit, bonfires that they believed would help them during the winter, so they took bits of the bonfire home and lit them in their own fireplaces.
Samhain was then meshed with a Roman holiday that was put in place to commemorate the passing of their dead. And also a holiday that celebrated the goddess Pomona who's symbol was the apple (bobbing for apples, candy apples). The Pope came around years later to make November 1 All Hallows Day (or All Saints Day). The night before became All Hallows Eve (Halloween). There were bonfires and costumes (just like with the Celtic celebration of Samhain) and parades. In the 1800s it was turned in to something more for communities and families. Parties and get togethers.
Trick or treating started out as a way to keep the spirits happy. For lack of a better way to put it. People would put food out on their porches as treats in order to avoid tricks. In medieval England it was called "souling". Starving people would go door to door on All Hallows Eve and say prayers for those that had died in exchange for food. There's an old Scottish/Irish tradition called "guising". Sending their disguised children door to door for money and food. They would only receive their "treats" in exchange for doing "tricks".
Halloween is what you make it. If you think it to be a miserable holiday full of devil worship and cult activity, then that's what it's going to be. If you think Halloween is just an overly commercialized holiday that's a ruse to make dentists money, fine, don't let your kids go trick or treating. Spare them from the cavities and possible sickness from eating too much candy.
But remember, what YOU believe is not always what everyone else believes. For me, Halloween was, is, and always will be about the fun decorations, interesting costumes, and candy for kids. It's fun. I mean heck, people go all out on their Halloween decor the same way they do for Christmas. And to be honest... I always liked going to haunted houses and being just a tad bit scared, wondering what was going to pop out of the dark behind me. But come on, the kids (unless they're raised differently ... but I won't get in to that in this blog) are in it for the candy. They're in it for the costumes. They want to have the coolest (or scariest/prettiest/most sparkly etc.) costumes and get the MOST candy out of all of their friends. Regardless of whether or not they're going to be able to eat it all.