One thing I like about working in a library is walking in the stacks. But when you do that, you see things you cannot unsee. It’s a large library (ten floors!), and keeping everything in order is impossible. Students put books back on the shelves any which way.
Oversized books should usually be shelved with the spine down, to protect the spine and keep the fore edge of the covers from splaying out. And I don’t even know how people can shove a book back on the shelf so the bookend is inside the book. But I see it frequently.