The first week (month?) of each new semester is filled with interactions in which we crush the dreams of a flood of new students when we have to inform them that no, the library did not buy enough copies of every textbook for every student. Sorry!
In a (probably futile) attempt to remind students that the library is not the same as the university bookstore, we made some nice, clear, colorful new signs to place around the library. We don't know if it really helped, but it made us feel better.