As a teenager, I woke up one night to hear the sound of artillery shells, and saw that my room was occupied by somewhat luminescent and translucent World War I-era soldiers, preparing to leave the trench for the machine-gun fed slaughter that was mistakenly called a "battle" during that war. I knew that I had to go with my comrades, as futile as it was, and so I began to don my backpack, pick up my rifle, and get ready. I was still in my room, but I knew that once I opened the door, I would be int he trench, and ready to fight. I went to the door, opened it, and saw my hallway...by this point, I had completely waken, and felt a bit foolish to be standing there in my backpack, holding a dowel that I had been keeping in my room for who-knows-what reason.
Commentary: I was unsure about whether or not I should include this story on this site. It's a description of events that occured to me when I was a teenager, and to which I have never attributed a supernatural cause. However, it does have a basic structure in common with many ghost stories, and like my experiences on the cliffs in Goleta, I decided to include it to illustrate a point that becomes relevant to anyone who works with personal accounts of hauntings.
The events that occured bore many of the features common to stories of hauntings: I woke up as a result of sounds, witnessed some truly weird spectres, and (in a slightly unusual, but not unheard of, twist) I joined these ghostly soldiers for battle. I could have viewed this as some sort of weird visitation or out-of-body experience, but instead I reflected on the fact that earlier in the evening I had been watching a television show about WWI-era trench warfare, and that the descriptions of the misery of the soldiers had really disturbed and gotten to me, and I also had been having trouble sleeping lately. Putting the two together, it became obvious that I was experiencing a mundane, if somewhat creepy, event.
The point to all of this is pretty simple. When I collect ghost stories from people, most of them tell me about events that occurred while, or shortly after, they had been resting, usually (but not always) in bed. The descriptions are usuall pretty simple - they see someone standing over them that vanishes, they hear strange sounds that they can't identify, or they perhaps even get out of bed and see/hear/smell something unusual. Invariably, the teller of the tale assures me that they were awake, and I hear those words "I know what I" saw/heard/smelt/etc. However, I have yet to hear one of these stories that is not absolutely compatible with near-sleep hallucinations. I also have never had a conversation with someone about such an experience in which they said that they had bothered to look for dosconfirming evidence before deciding that their experience was a supernatural one.
In short - when you are looking into people's stories, don't take everything at face value. They may have perceived something, and honestly believe that it was an external influence, when it was in fact something that came from their own physiology.
Sources: Personal Experience