do you believe in ghosts?

do you have any ghost stories... last year when i stopped over my friends house late february. we were outside of the farm house that he stayed in.. he went indoors i followed him a few minutes later. i walked into the house it leads into the kitchen and from there it branches into the living room or a hall way to the bathroom or stairs to the second floor where the bedrooms are. i didnt see my friend around downstairs so i went up stairs to see if he went to his room.. when i got up there his bedroom door was shaking violently... i called out to him but no one answered. so i thought that was a bit weird so i went down stairs and seen he was standing by the porch.