I have never knowingly seen a 'ghost' altho' I've felt a 'presence' on a few occasions what it might have been I can only surmise, but let me tell you a short tale.
I had been estranged from my father for some years..as had my brothers and sisters.
I had no contact with anyone who knew him or my step mother and hadn't had for about 4 years.
I'd just recently returned from living in Spain and I was asleep, and in my sleep (dream?) I awoke to see the face of my father in my darkened room.. his fully formed face as clear as a colour picture and I could hear him call my name very clearly which is what in fact woke me in the first place ...then he was gone.
It shook me up, I wondered why on earth I would have dreamt of him..and it played on my mind for a couple of years off and on. Eventually it bothered me so much that I decided to make some enquiries to ensure he was alright , a man who was always in very rude health and never a days illness so no reason for me to think anything was amiss .. I didn't want to make contact believe me, he was the father from hell a very violent human being who was the cause of my mothers' death .. hence our estrangement , but he was still my father. Anyway long story short...I eventually after jumping through many hoops discovered he had died , and it had been just about the time I'd had that dream 2 years previously...
I rpomise you this is the truth...I will never have an explanation for it.