Once, many years ago at my library, I was tasked with constructing some letter markers for our requested items shelving. It was more complicated than it sounds. I had to use my library's official font, color scheme, and minimalism. I wanted it to be immediately clear, especially to people using our system for the first time, where their last name would be. I used thick plastic inserts that stuck out from the front edge of the shelving and were very stable at the back. Looking down a row of books one could immediately see where each new letter started. I was pleased with it and it has worked well for years.
Then the pandemic came.
We expanded our request shelving so that it could be more spread out for social distancing. I was not involved in this project. It is pretty haphazard, with different ways of marking where things are and a motley assortment of different shelving and carts. My carefully made letter tags were cannibalized and used where they could be, abandoned when they couldn't.
I accepted all this. One does not survive more than 25 years working in an institution by getting riled be every little thing. One survives working in an institution by only getting riled by 70% of the little things.
It's called pacing oneself.
Today I was shelving some requested items, and I was in the "M's". But I noticed whoever had constructed the temporary system had taken my "W" sign and stuck it in there upside down. I don't know what happened to my original "M" sign.
I shrugged. Then I shelved all my books there, upside down.