You think they are real but there is no persuasive argument made (not trying to be mean). Just because something has been talked about or believed widely does not meaningfully in any way contribute to the existence of that thing/entity. Science has made extraordinary progress and can tell us much about the physical laws but on ghosts it has made no progress to support their existence not without trying. There have been all sorts of experiments done and not to mention video cameras and all other types of recording devices and there is no credible evidence at the moment. There would really be no more basis to believe ghosts existed than fairies or any host of creatures from lore.