Feeling a little on edge? Like someone is looking over your shoulder? Do you hear a creaking sound in an otherwise silent room? Wait! Was there something moving in the shadows? You could swear you just just heard a low kind of moaning sound, as though the saddest, loneliest creature in the universe were writing in solitary pain.
Buck up! It's Halloween!
The day after Halloween was once considered one of Christianity's holiest of days. Enshrined as "All Saints Day" by Pope Boniface IV, the holiday, like many Christian holidays (e.g. Christmas), borrows from earlier Pagan religions. This rite of the church was actually a two day thing, with a prepatory celebration knows as "All Hallows Eve". As such, Halloween was one of the holiest nights of the year, making way to All Saints Day. It's sort of like Christmas Eve and Christmas. The following day, November 2nd, became All Souls Day, to honor those who hadn't quite made it to sainthood. Since the focus of these days is about the dead rather than the various eternal beings (God, Jesus, angels, etc), you get where this whole Haloween death thing comes from.
All Hallows Eve and All Saints Day is borrowed from the pagan feast of Samhain and comes to us courtesy of the ancient Celts. Samhain is the Gaelic harvest festival. The fields have been harvested, things are starting to look a little dead, and winter is coming. The harvest is cause for celebration but winter, if you don't have central heating (as with the ancients Celts), isn't all that exciting. So the ancients did what most people do when faced with the prospect of some serious downer days.
They threw a party.
The days got shorter and the air got colder and finally, the solstice (which later became the ispiration for Christmas) arrived. The shortest day of the year. So the ancients did what most people do when faced with the darkest gloomiest day of the year prior to it getting brighter and (eventually) warmer.
They threw a party.
As you can see, whenever people are faced with momentous events, in and out of their control, they throw a party. And now, it's Halloween. Or Samhain. Or All Hallows Eve. Take your pick. Either way, it's a great excuse for a party if, as Vincent Price observed in Michael Jackson's "Thriller", you've got the "soul for getting down".