Me: “Can I help you?”

Customer: “Yes. Where it says ‘frame includes single-vision lenses’, does that mean I can’t have trifocals?”

Me: “No, it just means that the cost of the frame includes the price of single-vision lenses. If you wanted trifocals we would charge you the upgrade price to have them. They start at ¬£49 on top of the frame.”

Customer: “What’s the difference?”

Me: “Sorry?”

Customer: “The difference between single-vision or trifocals?”

Me: Oh, well, trifocals give you three different magnifications, into distance, intermediate and reading. Single-vision will only give you one of those.”

Customer: “Why can’t I have a single-vision lens that does all of those?”

Me: *checking her prescription* “…because your eyes need different levels of magnification to see each one clearly.”

Customer: “Why?”

Me: “When you are over forty, your eyes start to become lazy and have trouble focusing on close-up things, as well as things that are far away.”

Customer: “I’m not lazy just because I’m over forty! Let me speak to your manager! I have never been so insulted!”