First up, of many:
Patrons who place items on hold and then expect them to be ready within the next fifteen minutes.
Look, we don’t have a flashing light and siren that goes off whenever someone places an item on hold. And, even if we did, we do not have library gnomes who bust ass out to the shelf to pull your hold. Most libraries will pull holds once, maybe twice, per day. Huge libraries will pull holds all day but they usually pull from a list printed out once during the day.
If you want the item that badly, come get it.