Answer:
The impatient customer
The situation: An impatient customer may have been waiting in line longer than usual, they may be running late to their next appointment, or maybe they're restless while you search for a solution to their issue or concern.
How to handle it: Be clear and to the point without appearing dismissive of their demeanor. Explain transparently why there's a wait or delay without getting into specifics. Make sure an impatient customer knows that effort is being invested in resolving the situation.
Frame your answers in a positive light, too. For example, instead of saying that an item is out of stock, explain that a new delivery is expected by a certain date or that you are working quickly to restock the items in question