A story of my neighborhood convenience store.
At that convenience store, there's only one day when they don't allow use of the toilet.

I often go shopping when I'm awake at 4 AM in the night, but at that time the "toilet cleaning" plate is always hanging... However, although it seems like it's being cleaned, the light is never on; it's pitch black and showing no sign of a person being inside.

I thought it was suspicious, so I tried asking the clerk at the register. "Why can't we use the toilet at this time?"
Then the clerk was surprised and took a moment to gather herself. "Ah, err, w-well, it's being cleaned, I'm sorry," she said, giving a poor evasive response.

By some chance, this made my intuition flash. I tried lightly retorting by saying something like "Might they be out soon?" but then I was asked "Eh! How do you know? Have you looked?"
Still... on the condition that I absolutely wouldn't reveal the store name, that clerk told me the truth of the situation.

She said that around that time, when the door is opened, the face reflected in the mirror near the washbasin shows a clearly different expression than her own face... once it was laughing, once it was crying, and sometimes, when she looks into the mirror, the clerk can see her back reflected there...

Next time I too want to take a chance, and try standing in front of that mirror.