Oh dear, the technical scientific research I’ve done… I’ll try to simplify things. I’m not writing a dissertation LOL! Sorry, always love to have fun with what I’ve discovered about Ghosts…
Ghosts, in most cases, are souls whom upon dying were scared of entering the afterlife. Depending on their personal beliefs and what they did, right or wrong, when they were alive.
Some are good souls who decides to stay in between, due to unfinished business OR they want to stay as close as they’re now able to stay to their loved ones.
Some people believe in purgatory and that scares them more than or as bad as the eternal burning place. Cultures enter into this factor as well. Improper end of life rituals can cause one’s soul to be captured by the wrong side. The Chinese culture as well as the Islamic religion, require the body of a loved one to be buried very soon after death.
Otherwise their souls are at risk.
Generally, it’s believed that many people upon dying don’t realise that they’ve passed on. If no help comes from beyond the veil to guide them, they simply get lost in the aether.
Others know what’s happening to them as they see their bodies lying there, murdered and they want revenge, so… they stick around until the ones who did them in are brought to justice.
Finally, the ghosts that scares the bejesus from us are the tormented sent on orders from Hades.
Adding that too many people are doing rituals that are dangerous and end up opening portals which let beings from the depths of Tartarus come through onto our plane of existence.
Poltergeists have an easy explanation, building anywhere near a cemetery or onto a former cemetery or sacred burial grounds will bring forth beings that will try one way or another to get your attention.
Well I’m hoping that’s giving you a view that the paranormal phenomena is an extensive one and that at the end of the day, an open mind helps diving into an amazing field.
EG: The Amityville Horror… One family experienced horribly by staying and owning that house. Others who came afterwards didn’t… Who knows, hey?