Tell me about a time you went above and beyond for a customer.

"In my my past experience as a waiter at several restaurants, I've served my fair share of difficult customers. One customer in particular, a regular, was always a headache -- none of us ever wanted to serve him because he was rude and didn't tip well. One day, he was seated in my section, and I decided that I would really go above and beyond for him. I greeted him with extra enthusiasm, waited patiently as he asked lots of questions about the menu (which he was already familiar with), and met his various complaints with understanding and sympathy. Like usual, he sent his meal back more than once and complained regularly. But over the course of his meal, he began opening up to me as I served him patiently, and he ended up telling me that his wife had died earlier in the year. I began to understand him better, and he became a much more agreeable customer after that."