Person A says the number one rule of business is that the customer is always right.

Person B says the customer is NOT always right, like his customer who wants an auction system like eBay on a budget of $1,500.

Person A says Person B needs to shut up and listen to the customer.

Person B says

I AM listening. They want something like Ebay for $1500. They want me to build a full Ebay clone this weekend and then tweak it until they’re happy over the next two weeks. I have listened carefully and diligently and have confirmed multiple times. This is definitely what they want. They’d also like time travel, but they don’t need that until April.

The point I’m making is that there are many reasons why just listening to your customer and giving them what they ask for is often not a good idea - for you or for the customer.