Ghosts love rocking chairs. Also mirrors. Seeing a spirit in a mirror, and then turning around, and no one being there....
However,
While I was vacationing in Spain two years ago with my family, we stayed in a hotel in Cadiz - one of the oldest cities in Europe. This is the city where Napoleon's fleet set sail from prior to their annihilation at Trafalgar, this city has been sacked numerous times and has seen fighting since the earliest days of history. Cadiz once even held a port for Egyptian sailors.
We had driven to Cadiz from Gibraltar and needed a place to stay. Most of the hotels were already booked and I was worrying that we might have to sleep in the car. Finally, on a side street we found the "Hotel del Sol", a very old little place run by two young men. They happened to have two rooms, and my wife and I split up the children and took the rooms - me sleeping with my youngest child, and my wife with the older one. I was in room 14.
I was tired, so immediately fell asleep. At some point, I heard a loud BANG come from my bed, which woke me up. I thought that I dreamed it, and was now wide awake, when again BANG. This time it woke up my child, and not wanting her to be scared, I said "Go back to sleep, Daddy bumped himself">. I then spent the next five minutes trying to make the bed make this same noise... jumping on it, shaking it, to no avail (silly huh?). Finally, I figured, this is stupid. I'm going back to sleep. As soon as I dozed off, something began shaking my bed very violently. That was it. I could no longer sleep, and was worried about my child. I then went into the bed with her and tried to sleep again. Until the morning light I had to keep getting up to push a chair against the wall to stop it from making noise, a nightstand which was gently rocking, and other odd things. I felt too silly to go into the room with my wife... I didn't even want to tell anyone about it.
It was as if there were a nasty little child in the room that would wait for me to just doze off, and then either make some loud noise or shake the bed to wake me up. It was not much fun.
I spent the next night in another old hotel in Seville, and had a hard time getting to sleep after the previous night. Thankfully, nothing unusual happened at all.
And I don't even really believe in this crap. But it really happened. I don't understand it, this does not abide by the laws of physics.