Know the difference? Most people don't. I heard throughout grade school that Halloween was the devil's birthday.
Traditionally, beggars threatened a trick if not given a treat. Those tricks could be soaped up windows or overturned outhouses. The custom of going door to door came from Celtic and European origins where the wealthy would dispense some of their bounty. This usually happened around Christmas. December may have been way too cold, which could have caused a change.
The habit of dressing up is theorized to come from the traditional belief of evil spirits following you home after a burial. Ancient people never knew why someone died. They thought something evil killed them. The spirit or demon could attach to the mourners. To trick the sickness or entity, they'd don costumes, often animal heads. Under the belief they were being followed, they tried to enter other homes, as opposed to their own to trick the spirit. Most didn't answer their doors knowing someone had died in the community. Those caught answering the door probably offered something to make them go away.
Knowing all this, it makes sense that costumes might be ghouls, ghosts, zombies or even skeletons. Can anyone explain why all the fairy tale characters in abbreviated outfits?
Haunted houses spring up everywhere with hefty admittance fees demonstrating people like being scared. Part of this is the same reason people ride roller coasters. There's the possibility of danger making the person feel alive. Both haunted houses and theme park rides are in controlled environments assuring us we'll survive even before we partake of the dubious pleasure.
Is Halloween the devil's holiday? According to Pat Robertson, letting your children trick or treat may cause them to be demon possessed. An interesting theory, considering all those stories about needles and razor blades in apples and candy were only urban myths, never documented in any form.
Halloween could have evolved from a number of harvest festivals and regional events. In the end, people just wanted an excuse to party. Samhain is an entirely different event.
Unlike the cartoons witches flying in for a big party, Samhain is a time of contemplation of those who passed and divination. Photos of the dead are placed in prominent places, even altars are made. For one night, there's a pause to remember the dead and their contributions.
A meditation or quiet ritual may solicit those who passed for advice. Often a scrying mirror, Tarot cards, or even staring into a candle flame or crystal are used. Knowledge of the future isn't always forthcoming, but sometimes it is a mental whisper or a feeling of rightness.
A dumb supper is held after the ritual with a place setting laid for the absent member. It is referred to as dumb because the deceased person cannot speak. Samhain is a far cry from the demonic celebrations that some might imagine. There's no reason a person couldn't celebrate both Halloween and Samhain.
People usually wear black on Samhain for a variety of reasons. It symbolized the longer nights and death. Originally, witches wore black to escape into the night from the witch catchers.