The interviewer is hoping to hear that you handle these situations with poise and professionalism while not allowing them to get the best of you. Candidly share a time when you had an upset patron at the library. Explain why the person was upset, and express what steps you took to help the guest. Be sure to mention that you know the customer was not directly upset with you; they were upset with the situation. Share that you understand your responsibility is to serve the customer helping them be as happy as possible before leaving the location.