Halloween

It is better not to demonise nor canonise Halloween. It is to be taken in the context of the anglosaxon-celtic cultural background. Like Onam in Kerala, it's a harvest festival. It's perhaps because of it, the role of the tomato, and pumpkin ... It is also a new year celebration, the beginning of a new time. As the (re)beginning of time, the dead are believed to return homes. Afraid of evil spirits the living would disguise their face to escape from them.
Gradually all these became fun and game.
Many of them who celebrate don't even think about a God to dishonour or a devil to be celebrated. Some people like to see devils everywhere and they do find them. People who are religious and God's people engaging in war, hatred, greed, power-games ... are all for God's glory. There, in fact, beliefs are worshipped than God, and evils can be easily justified.