I am saying this very positively that there are no ghosts but those are your belief and way you were listening and reading about them. Some of it comes to your mind due to upbringing and company you keep..
yes..
also fairy tales which we learn from our grand mothers from childhood.
But we Hindus believe in spirits of our family, for which we do 'Bali' in this holy month of karkidakam...just to remember those persons, though we never see them. :)
It's our respect towards them, as it's believed holy spirits stay inside the home and protect family from bad experiences. Also bring prosperity to our family if they are given respect.