Well I think "ghosts" are a figment of someone's imagination.
I believe in "spirits" .
I do not believe that the "dead" come back to haunt and have unfinished business. Once dead they are dead unless raised from the dead.
Angels I believe exist however they are not our loved ones that passed on, as most seem to think. They were on the universe before humans.
I believe that there is something out there that some are seeing/hearing for sure, as I have heard my name yet no one is there.
Those little bumps in the night are just that and since the beginning of horror shows they have become ghosts.
There are so many people seeing something that they all cannot be lying however one story spirals into another.
But this is just my opinion it does not mean I am right.