I don't believe in ghosts.
I do recall the house we had in the mountains of Segovia, replete with Tolkien-level spider invasions from nearby pine forests, large, hairy, and difficult to stomp, often moving in large groups; quite unnerving. There, in that home, my wife swore she'd been shoved from behind while ironing, and had frequently felt someone pressing down on her when resting. She claimed to have seen an old women as a ghost, too. I, too, thought I imagined a strange touch one time. All explainable and owing to whatever real causes were in play, physical or psychological, surely.
However, when the furniture movers were just finishing up late one evening as we left for a new home elsewhere, they both came running out into the street claiming an old woman's ghost was haunting the now-empty house, clearly in shock. Don't really have an answer for that.
Anecdotal, good for camp fires.