I don't work in a shop but maybe someone will find this funny.
I can across a fellow on his 2 week old top of the line Trek Project bike who was walking with his cleats in his hands. I stopped to see if he needed anything. He was livid over the flat (pinch flat on bridge lip). I offered to fix it for him. "No, I called the shop and they are sending someone". I was like they are 35 minutes from here, I can fix it in 5 minutes. I explained he probably has a pinch flat and asked if he checked his tire pressure. I might as well asked him is he spoke Chinese. He blamed the shop, the tire company.....for putting lousy tires on the bike. I offered once more and let him stew in his ignorance and thought the shop should just give him a refund and cut their losses.