Back when I was in High School in Sydney in about 1977, my parents were house hunting (again) & Mum & I were checking out a house in Killara they were interested in. We were both impressed by the welcoming atmosphere in the house as soon as we stepped through the front door into the wide, sunlit hall. There were one or two pieces of furniture in the hallway including an antique tray table which had really old castor wheels on it - the type that don't roll very easily even on smooth floors like that hall. The rectangular table was standing slightly at an angle to the wall, the front edge was about 2 inches further out from the wall than the rear edge.
I noticed all this because we had been standing in the hall chatting to the house owner (Mrs C) for a while when a man came to the front door. Mum & I were facing away from the door & towards the table, Mrs C at the door had her back turned but her visitor at the front door had a clear view of it. No-one was standing within 5 feet of the table & no-one was moving around to cause the floor to move but that table very smoothly & deliberately moved in towards the wall to sit neatly parallel to it.
The silence was deafening! The man at the door stopped speaking for several seconds then pointed at the table & in a very shaky voice said "That table just moved!". Mrs C just sort of said "hmmm" & concluded the conversation. He left, she turned back to us & continued our chat as though nothing had happened. She may have been worried that Mum would have been put off buying the house but frankly, we saw it more as a greeting than a threat. Suffice to say that was only the first encounter of several I had in that house.