Do ghosts/demons/evil spirits exist because people believe they exist?

you've heard of those sorts of stories where people have encountered ghosts and did not realise at that time that they were ghosts, but learnt later on that the description of the person who they encountered matched the description of a dead person
.......

if you've seen a hypnotist make a mockery of people on stage, then you know that people can be very easily made to completely ignore reality
now if people hype you up about a supposedly haunted house, maybe they are unconsciously doing what a hypnotist consciously does
so you go into the supposedly haunted house and experience things which are not there
i think most of the time this happens

also the hyping up doesn't have to be immediately prior to entering the so-called haunted house, the non-real experience of seeing ghosts etc. could also occur because of some horror movie which you watched as a kid, and these things were lying dormant in your mind, and now that you've entered a house which reminds you of a 'haunted house', these past memories/suggestions surface and might mess with your mind

i am not a skeptic, but i think in most cases, people are simply misguided by their emotions
what is required is a person who will encounter a terrifying ghost and still feel no fear, if such a person checks out a haunted house, he/she will be able to more accurately tell if the place is haunted or not