（Contributed by Karl)
While deceased ancestors are universally regarded as venerable, and often believed to have a continued presence in some form of afterlife, the spirit of a deceased person which remains present in the material world (a ghost) is regarded as an unnatural or undesirable state of affairs, and the idea of ghosts or revenants is associated with a reaction of fear. This is universally the case in pre-modern folk cultures, but fear of ghosts also remains an integral aspect of the modern ghost story, Gothic horror, and other horror fiction dealing with the supernatural.
Ghosts were often thought to be deceased people looking for vengeance (vengeful ghosts), or imprisoned on earth for bad things they did during life. The appearance of a ghost has often been regarded as an omen or portent of death. The idea of ghosts can also be considered a tradition for certain cultures, many believe in the spirit world and often try to stay in contact with their loved ones.
Yūrei (Japanese ghost) from the Hyakkai Zukan, ca. 1737
Aokigahara: The forest at the bottom of Mt. Fuji is a popular location for suicide. This gives rise to a widespread belief that it is haunted. It was featured on an episode of Destination Truth on the SyFy Channel.
Okiku’s Well: The well at Himeji Castle is often said to be haunted by the ghost of Okiku. She is supposed to rise from the well at night and count to nine before shrieking and returning to the well.
Belief in ghosts in European folklore is characterized by the recurring fear of “returning” or revenant deceased who may harm the living. Also, English folklore is particularly notable for its numerous haunted locations.