Balderdash!
I think a lot of people just enjoy scarin' the bejeez out of themselves. Hence, the popularity of horror movies, or horror books, which I neither watch nor read.
Or, scary dreams. Why in the heck do we humans do that? But, those are dreams. Not reality.
I don't doubt the sincerity of people who experience, or see, ghosts. But I also believe they are just figments of their imagination.
Sixty-nine years old, and I have never seen or experienced a ghost. If I come across one before I punch out I will change my view, but, based on my experience to date, I think it mighty unlikely.