I got frustrated a lot in my preschool years because things would keep disappearing of mine, then show up in the oddest places, such as jammed behind radiators, in obscure holes in the wall. I 'knew' who it was. I never had a name for them, but it was those people that lived in our house with us. I don't remember ever seeing these people, but knew they were the root of a lot of little mischief I often got into trouble for. My parents say I never had imaginary friends. I don't know the validity of something I've never seen, but I've 'felt' too much about somethings in and around our house to totally disregard this.
The first actual memory I have was from when I was seven. I'd got into trouble for removing something from attic(1) and not putting it back. I came through my parents room and opened the door to the attic. There was only one skylight in the attic at this time. The light was faint through it. My father's work area was just inside the door to the right and there was a luminous green display clock there. However, when I opened the door; at the far end of the attic, a shady white image moved quickly from one side of the attic to the other (behind some storage area). I was scared shitless, ran in the shortest distance I could into the attic, threw down the thing I needed to put back, and ran down the stairs to the living room as fast as I could. Terrified, I reported the image to my parents, they first tried to explain that it was the skylight, 'It's never done that before.' and then they tried to blame the flashing display from the clock, 'The clock doesn't move side to side.' They were skeptics and put it down to fanciful imagination.
When we moved into the house, we found a few things in the attic that might have been left by the previous owners. Things such as WWII casings for ammunition.
My parents never left me alone at home until I was about 11. A few times, when I'd been in the house alone, odd things would happen. Keys placed in the middle of the huge breakfast bar in the kitchen, would smack into the middle of the kitchen floor. When I was in my parents room, I would get so terrified of the attic I couldn't stand to be there. (Later when I was 16, this was where my bedroom was, and where at 17 I tried to kill myself). Shadows would move in the corners of my eyes. (Strangely enough, my mother's noted this happening in one area of the house. She doesn't spook easily and she knows the house better than I do.)
Even other people would notice things. One evening, my mother was playing on her organ, this had been my paternal grandmothers and she left it to my mum. I'd disappeared up into the attic to give something to my father. I came down to find her talking as if she was talking to someone. When I appeared to her side, she looked shocked. 'I felt you behind me.' She picked up playing the organ really well and she sometimes feel that my grandmother is somehow helping her. Very odd for my mother to say stuff like this.
There's been times when we've been sitting in the living room and very suddenly the most fragrant rush of air will drive by us. Yes, there's been flowers in the room some of these times, however, there are no draughts that hit the living room in that way.