I'm an atheist and I don't believe in ghosts, but I do think there might be something in residual energy type theories
When I was a child, we lived in a tiny little 2 bed council house. It was a cute little place, solid and cosy
Something stood at the bottom of my bed, watching me, almost every night of my childhood. I could see the black was deeper where it stood. You could almost see a shape due to this intense absence of light. Sometimes my mother would leave the hall light on, it would reflect against the wall, and you'd see the shadow moving. Many times I'd wake up, and in that sleepy half asleep state, feel someone standing beside me, touching my face. I'd assume it was my mother, but then I'd hear her out in the garden or in the shower etc, or I'd ask her and she'd say it wasn't her.
I never felt scared, just odd. The feeling of being watched got a bit much at times. I'd chat to it sometimes. Once I kept a box of toys in its corner, and every night I'd wake up to all the battery powered items going off at once. Eventually I moved the box and this stopped happening.
We moved when I was about 10. Many years later, when I was an adult, my mum bumped into a lady who turned out to be one of the first residents of that house, back in the 60s when they were new builds.
She had had a child, a little boy who had been very unwell since birth and wasn't expected to live more than a year. He made it to four, and died peacefully in what would later be my bedroom.