I love this thread. Here's my first one. I am very rational and always look for a practical/scientific explanation to stuff (even though I actually love scary stories!) but these two things I have never been able to explain.
When I was 16 I got a job in a bingo hall and I worked there for 5 years. Our hall was an old converted opera house which had been built in 1902 and converted to bingo in the 60s. (It's now a Wetherspoons!)
Like most old theatres this one had a few "resident ghosts" that people used to talk about. The older staff used to sometimes play little tricks on the newer ones. We would tell them that we'd give them a tour of the closed-off parts of the building - which were pretty interesting, the old dressing rooms, etc, and the "gods" - the highest seats up near the ceiling, which were unsafe for the public now. Then one of the other staff would get in position and hide, then start giving ghostly moans when the new staff came near. All fun and games.
So in 5 years working there I never felt or saw any presences although several of the girls claimed to have seen "The Blue Lady" walking through the gods on various nights. Frankly there was so much cigarette smoke on most nights that I'm not surprised if everything looked blue!
I worked in the cash office, so most nights I would be the last person to finish. We had a policy that there had to be at least three staff in the building at all times as we were a high risk for robbery. On this particular night some of us were all going for a drink after work, so about 10 people were downstairs waiting while I locked up upstairs. I locked the cash office, then the outer office, did a quick check to make sure nobody was in the manager's office. Locked up the middle corridor and the outer corridor (and yes I did have a bunch of keys as big as your fist. There were a lot of locks.)
As I finished locking the last door and turned to go down the stairs, something poked me hard in the back. I gave a little "oh!" and turned, already saying "For gods sake Bob [resident chief practical joker], you idiot!"
There was nobody there. I was standing on my own, at least a meter from the nearest door. I looked down at the floor, kind of bemused, thinking maybe some of the ceiling decor had fallen down and hit me. (It was covered in ornate cherubs and rosebuds.) Nope, nothing there. I walked through the doors to the left to check the upstairs bar - nobody there, all lights off. I went the other way to check if anyone was hiding in the circle seats. Nope. I went back to the corridor to check I'd locked the final door. All secure.
I went downstairs to the front desk, still convinced that someone had snuck up on me and somehow got away without me seeing, but everyone was still there (including Bob.) And these guys weren't hugely sophisticated at practical jokes - everyone would have been hiding grins or nudging each other if they'd been playing a trick. I said "You guys didn't see anyone go upstairs, did you? Just now?" They all just looked baffled. The last customer had been ushered out at least half an hour ago. I said "I felt someone poke me in the back, at the top of the stairs!" Of course there arose a chorus of "It was the ghost!!! OMG let's get out of here!!"
We locked up and set the alarm as usual. Nothing set the alarm off that night.
It was so bizarre. It was a pretty hard poke, exactly the sort you would give to someone you were trying to scare. I didn't have a handbag or a jacket that might have flapped onto my back (and the feeling would have been completely different anyhow.) I hadn't been thinking about ghosts or ghouls - I just wanted to lock up after a busy Saturday night and get to the pub in time for a pint!