I suspect the same thing as old hack, the sales staff being pleasant, since you asked. If you want to have another go, I'd ask to speak to the manager, they will likely give you a more realistic answer. You'll occasionally see a self pub/vanity press book in stores. It's always that the Author was local and came in and asked the store to put a copy on their shelf. Some of them will oblige to be kind and because that Author is also a customer, the customer is always right.