When I was very young I had an imaginary friend. Once I feel out with this friend because she was "just an idiot like everyone else".
Also I was scared of the dark, or more scared of the shapes of the things on the shelves, how they looked in the dark. So I would lie in bed at a weird angle with just my face sticking out so that I could breathe. All I could see from here was the blank wall so I couldn't see the other things I thought were so scary.