Sounds like it was one of the simplest requests that a customer could make. Some people just need to be “right” and they need it validated. I believe this is one of the reasons why we have so many issues in the world, but I digress.
A long time ago, and I say this with all sincerity and not in a boastful manner; I decided that I would do whatever I can (within reason) to make other people’s lives easier. I learned that it makes my life a lot easier. If it were just one sammich, I would have marked it and bid the customer a good day. Otherwise, I’m just seeking conflict.