I often wonder. How do so many people have similar experiences in "haunted" places if spirits didn't exist? How do Ouija boards work? I recently purchased one and...I now know why so many people fear them.
I've had many experiences in my life that cannot be explained, such as record players coming on by themselves (the switch had to be manually flipped and the needle set), old toys in display cases that changed position and received inexplicable damage (it remains locked and only I have the key), ceiling fans that turn without being on (and no breeze in the house), etc.
I know it sounds ignorant to say, "I have no way of explaining these things, therefore it must be spirits", but that's all I've got.