Weeding. Just like in the garden, it has to be done regularly, or the job gets out of hand. The good plants have no room to shine when the weeds are choking them out and taking up the shelves.
While some of my colleagues enjoy it about as much as root canal, I love weeding. I’m in the stacks at least once a week looking for likely candidates. Just as a garden needs to be cleared of the excess plant material and weeds choking out the blooms; so to a library needs to be cleared of old, worn, and disused materials.