Automakers: Don't Ask Customers What They Want
In all the cases here, what the customer wanted was available in some other car. Thunderbird owners said they wanted 4 doors. But there were several 4-door fast cars on the market which they didn't buy, so you shouldn't believe them.A common situation in startups is, there are two current products on the market A and B. A has 99% of the market, B has 1%. The amount of feature X (speed, ease of use, scalability, ...) they provide is limited:    ---A----B-------------------------------------->  X

A startup is proposing to make product C. It will be awesome because it provides way more X:    ---A----B---------------------------------C---->  X

But you need to ask, if people really value X, why aren't they already switching from A to B?It happens all the time that startups ask customers, "Do you want a product with more X?" and they say yes. But if they're not already using the product out there with the most X, you shouldn't believe them.