I have worked night shift for most of my working life, so a busy bathroom was never a concern.
However, I do have an interesting bathroom story:
One place I worked at was in an older multi-story office building downtown, the kind with a marble-column facade and brass fittings in the elevators.
One night around break time, a female co-worker came to me and said "come here, I want to show you something".
She was the 'weird' girl on shift that I was on friendly terms with, and had gotten to know her well enough that she actually wanted to show me some curiosity, and not making overtures of fraternization.
She went to the shift manager's office (not unusual, it was sparse,always open, and shared between 3 shift managers and various personnel) and grabbed a key from the top drawer.
She then took me to the elevator and we went up 3 floors.
When the door opened, we got out and she led me around a corner where a women's bathroom was.
"It's ok, there's nobody here" she said and opened the door.It. was. immaculate.
White marble counters and floors, brightly lit, a modest chandelier hanging from a cathedral ceiling, the whole 9 yards and then some.
Most curious was a wooden door at the other end, marked with a brass plaque as "The Quiet Room".
My co-worker took me to the door and opened it with the key she had purloined.
Inside was a simple carpeted room about 6 feet by 10 with two orange tweed-covered chairs, a couch, two of those old two-tier coffee tables popular in the '70s with a desk lamp and stylish ashtray on each one.
A single large window over the couch offered a heady view of the city northward.
She kneeled on the couch to face the window, opened it, lit a cigarette and said "Isn't this place great? I wish it were on our floor".
I lit one for myself and joined her gazing over the city lights, chit-chatting until break time was over.
One of my best cigarette breaks ever, and we only had opportunity to go there twice again after that before she went back to working on day shift.
A year later, the office closest to that ladies' room expanded their office into the space the "Quiet Room" occupied.