Another point to add about spirits or ghosts, when they are here visiting they change the atmosphere in the room. The change will make us wake up if we are asleep, and it also causes the hairs on the back of the neck to stand up and get a prickly feeling in the skin. I don't doubt that these are the feelings that make it feel "evil" because for the most part it is the unknown - especially for a child it would be very frightening. As for us older folk, I'm sure much of it is from the "programming" we receive while growing up.