I think the general idea is to look for what is now called "pain points". These are basically the friction points in a process - the parts that cost a lot of ti

I think the general idea is to look for what is now called "pain points". These are basically the friction points in a process - the parts that cost a lot of time, effort, money, or the parts that have a higher likelihood than the rest of the process to fail. You then either try to make these parts of the process better, or reengineer the process to eliminate these parts. For your example of Touch ID: The way to figure out that this is a product people would want by the interview process is not to ask them about a fingerprint scanner, but to identify logging in to a phone as a "pain point". This particular use case of touch ID existed long before smartphones. It's just that smartphones were the first mass-deployed login device that are used sporadically but frequently during the day in order to justify the deployment of it. While fingerprint login was also used in laptop computers before smartphones, the lack of touch ID doesn't cause as much friction because people log in to their laptops less frequently than a phone, and because a laptop comes with a much easier to use keyboard than even a phone's login screen. Plus you've got the cachet of iPhones, and the universal implementation of features that Apple brings to its devices. How many iPhone users really cared about touch ID? I don't know. Fewer than their are/were people with touch ID enabled iPhones though. Which wouldn't be the case if Apple had made it an optional purchase. P.S. I hate the term "pain point", but it's what's used these days.