My (then) six year old niece used to tell us about a lady in grey who followed her around the house. One day she got very upset and said she wanted the lady to leave her alone. So I thought I'd be clever and started kicking out and saying 'leave her alone'. My niece looked at me as if I'd gone bonkers. 'What are you doing?' she asked. 'Kicking her out!' I replied. 'Well maybe you should go over there to where she really is' replied my neice pointing over to other side of the room
I don't think my son's friend was a ghost though. He used to talk to him all the time and told me his name was John. John's mum and dad were Ron and June and they lived on the moon!

So I think in some cases, yes, they may be ghosts in others I think they're figments of vivid imaginations

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