I work at a dollar store just down the street from me. It's been there for over 10 years and it has been an ok first job.
I get stuck with night shifts a lot, but in these instances it's been alright since most of the weird things that do happen are at that time. My coworker who was with me on these occasions also believes there is something lurking around in the store after closing hours as well.
We've both seen shadows darting down aisles on the other side of the building. I would search around to make sure no one had hidden themselves in the store and no one had. There's been random voices that will make my coworker stop mid sentence to look around because she swore she heard it. We have a radio in the back room but it's never turned up loud and the doors are always shut plus we're at the front of the store when we hear these voices so I don't believe it's that. Footsteps that sound like they're right behind us but when we turn around nothing is there.
Night 1: It was after closing and I'm moping the floors on one side of the store. I look up down the aisle directly in front of me and something catches in my peripheral. I look to my left and see a shadow probably 5'8 to 6 feet tall run by on the opposite side of the store. After it disappears behind an end-cap, a sack of plastic cups falls from the same shelf like it was knocked over by someone's hand. I go over to pick them up and look around, no one is there. I look to the shelf to try and find a reasonable explanation as to why it fell off like it did and I was instantly warded out. All the bags of cups were still neatly set in place not thrown around haphazardly like I was expecting. The shelf was nice and level so they wouldn't just slide out. And they were heavy enough to not get blown over. I had seen them before I started moping so none were on the edge. Something pushed it...
Night 2: Once again I was moping after closing and I'm standing in front of the doors to the restrooms. Both doors are open. One staying open by itself and the other propped open by a wet floor sign. The back storage rooms double doors are both already shut and the office door at the front of the store is open because my coworker is in there doing her nightly management duties. So I'm walking down an aisle when I hear plain as day the sound of a door slamming closed. I instantly put the mop down and go check the restroom doors, both are still open like I had them. I check the storage doors both are still shut. At first I thought maybe my coworker had walked back there to put something up but I go look towards the office room and she's still sitting at the desk. From the time I heard the sound to looking at the office would not have given her enough time to go there and back, so it wasn't her. And we are the only two people there at night. Needless to say I finished moping in record time and got back up to the front. It's dark in the back because some of the lights shut off automatically after a certain time. Makes it even more spooky being alone.
There's been more instances like this with objects falling for no valid reason. Half the time when these things happen it's been after one of us has joked about there being a ghost. Maybe there is. And if it isn't one then what could it be?