I provided an example of a time when a customer was very frustrated that there was a hole in the shirt she had bought. I was able to speak calmly with her and offer her a full refund, which seemed to diffuse the situation.
I talked about recurring scheduling issues, and how I'd solved them by establish regular meetings with all those involved where I would state the schedule clearly, and then followup with regular emails.
I recently had a customer who needed something returned. She didn't provide adequate information about the items being returned and I was unable to help her until it was too late and the issue was escalated to the Vice President of my company. I got really upset and my manager told me that I should have gotten someone else involved sooner to avoid the issue.
I discussed the convenience of having one in a fast-paced shopping environment--being able to make returns without needing a receipt, having discounts applied to purchases without needing a coupon, etc.