I have several stories but I'll start with this one. When I was in my early 20s and destitute, two friends and I squatted in an old house that was condemned and going to be torn down the following spring. Because we had no front door locks (and were too poor to buy the hardware), we each put a lock on our bedroom door. One day I came home, unlocked my bedroom, and the entire contents were strewn all over! There is no way anyone else could've gotten inside. Nothing was stolen. Since there had been inexplicably misplaced items in the house, all 3 of us had "felt" ghosts before and heard unexplainable noises, I just assumed it was the ghosts. The next day I put a note on my door:
"Dear Ghosts,
We don't mean to bother you but we are very poor and have nowhere else to live. We don't mind that you're here, but you make me sad when you mess up my room like this. I mean you no harm, and it would be greatly appreciated if you wouldn't mess things up again."

We still heard noises after that, but nothing in the house was "moved" again. And a visiting friend saw an apparition of himself fallng down the stairway, and would not come back. But I was not afraid.