At a graduation party, a retired fisherman told me I was the first person ever to thank him for 30 years of work. It stuck with me. So I asked the research a question: does a simple, authentic thank-you still matter for customer loyalty and growth in the age of AI? The psychology is clear and freshly confirmed. The business case is real. And the part everyone is asking about, whether AI can replicate it, is exactly where the data runs out. Here is what the evidence says, and