The better you get at being a librarian, the more you get promoted. The more you get promoted, the less real library work you get to do.
Are you good with the public? We'll stick you in an office and let you crunch numbers.
Are you good at cataloging? We'll let you manage people with difficult personalities.
Are you a good researcher? We'll let you draft strategic goals and other management rubbish.
Lesson: don't let anyone know you're good at what you do.