I grew up in a haunted house, and if they are around, they generally come out to play. When my ex and I first moved into a haunted house, he did not believe, and the ghost made it clear that they do exist.
It would ring the phones in certain parts of the house and not others, and start the vacuum cleaner and move it (not self-propelled). My Great Dane would actually back out of the living room with his hackles up when ghost wanted the room. One other time, he tore an advertising sign off the wall and threw it down where I had been standing a minute earlier.