This is kinda interesting.

I can honestly consider myself religious stupid. All I honestly know is Catholic. So help me understand and let me know if I am wrong...Christians feel that halloween is a day to celebrate the evil spirits from hell? (since they dont believe in ghosts) That would explain why they wouldnt celebrate it.
As a devout Catholic, I can honestly say that I attend Mass on Halloween and also celebrate with our Parish the festivities of the day. We call it Trunk or treat and honestly, kids are just that kids...
So here is the origin of the Roman Catholic Religion and Halloween:
The history of Halloween goes back more than 2,000 years. The earliest celebrations of Halloween were among the Celtic people who lived in the areas which are now Great Britain and Northern France.
The Celts were people who worshiped the beauty of nature. They worshiped a Sun God and believed that without him, they would not live. They also worshipped Samhain who was the lord of the dead and of the cold, dark winter season. They believed that on October 31 Samhain would call together all of the dead and these souls would take on the shape of an animal. They believed that all creatures wandered the Earth on that night. This was called the Vigil of Samhain.
The Druids, which were the priests of the Celtic people, would build fires on the hilltops in belief that the large fires would help to strengthen the Sun God, and give him power enough to overcome the lord of darkness so that the sun season could continue. They believed that the fires were sacred, therefore they burned dried crops and sacrificed animals to help strengthen the Sun God. At midnight they stop worshipping the Sun God and start to worship Samhain because he will be the ruler for the next six months. This is the starting of the new year. They perform ceremonies through the night to ask the spirits to tell the future of the upcoming year. In the morning each household receives an ember from the fire, this ember is used to start fires in their own homes with the belief that it will ward off evil spirits in the new year.
The Celts continued with their ceremonies until they were conquered by the Roman Catholics. The Roman Catholics brought with them their own customs and traditions. They had established All Saints Day or All Hallows Day on November 1. This was a day in which all saints who did not have their own declared holiday were honored. The church had hoped that by establishing this holiday, it would do away with the Vigil of Samhain and the other ceremonies and celebrations held on October 31 through November 1. But this was not so. Soon witchcraft came about, and October 31 was renamed Night of the Witch. It was believed that the devil and all of his followers (demons, witches) would come out on this night to perform unholy acts to make a mockery of the All Hallows Day celebration. These ceremonies and celebrations continued and October 31 was then called All Hallows Even. It was a night for superstitious beliefs and mystery. Through the years the name was shortened to Hallowe'en and then to Halloween.
Ancient Origins: Halloween's origins date back to the ancient Celtic festival of Samhain (pronounced sow-in).
The Celts, who lived 2,000 years ago in the area that is now Ireland, the United Kingdom, and northern France, celebrated their new year on November 1. This day marked the end of summer and the harvest and the beginning of the dark, cold winter, a time of year that was often associated with human death. Celts believed that on the night before the new year, the boundary between the worlds of the living and the dead became blurred. On the night of October 31, they celebrated Samhain, when it was believed that the ghosts of the dead returned to earth. In addition to causing trouble and damaging crops, Celts thought that the presence of the otherworldly spirits made it easier for the Druids, or Celtic priests, to make predictions about the future. For a people entirely dependent on the volatile natural world, these prophecies were an important source of comfort and direction during the long, dark winter.
To commemorate the event, Druids built huge sacred bonfires, where the people gathered to burn crops and animals as sacrifices to the Celtic deities.
During the celebration, the Celts wore costumes, typically consisting of animal heads and skins, and attempted to tell each other's fortunes. When the celebration was over, they re-lit their hearth fires, which they had extinguished earlier that evening, from the sacred bonfire to help protect them during the coming winter.
By A.D. 43, Romans had conquered the majority of Celtic territory. In the course of the four hundred years that they ruled the Celtic lands, two festivals of Roman origin were combined with the traditional Celtic celebration of Samhain.
The first was Feralia, a day in late October when the Romans traditionally commemorated the passing of the dead. The second was a day to honor Pomona, the Roman goddess of fruit and trees. The symbol of Pomona is the apple and the incorporation of this celebration into Samhain probably explains the tradition of "bobbing" for apples that is practiced today on Halloween.
By the 800s, the influence of Christianity had spread into Celtic lands. In the seventh century, Pope Boniface IV designated November 1 All Saints' Day, a time to honor saints and martyrs. It is widely believed today that the pope was attempting to replace the Celtic festival of the dead with a related, but church-sanctioned holiday. The celebration was also called All-hallows or All-hallowmas (from Middle English Alholowmesse meaning All Saints' Day) and the night before it, the night of Samhain, began to be called All-hallows Eve and, eventually, Halloween. Even later, in A.D. 1000, the church would make November 2 All Souls' Day, a day to honor the dead. It was celebrated similarly to Samhain, with big bonfires, parades, and dressing up in costumes as saints, angels, and devils. Together, the three celebrations, the eve of All Saints', All Saints', and All Souls', were called Hallowmas.
Oh, by the way, God did not create ANY holiday's and Holy Day's other than the Sabbath have been created by members of the church. I do not believe God will judge you one way or another on how you celebrated holidays but will notice if you missed out on Holy Day's. **Disclaimer** these are my personal feelings towards this matter.