You want to learn about what's already in their heads. You want to avoid putting things there.

You have this idea that you think is awesome. You want to have that broadest group you possibly can. You don't want to just talk to 1 type of person and learn that, you want to get familiar with the space.

Most startups are not just built for the person who is using them. When you do that, every now and then you get really lucky and... are representative of some huge class of people who all want the same thing you do... but very often that just turns into a side project that doesn't go anywhere.

Who would you talk to? That is the first question for almost any startup that you need to answer. Who is my user and where am I going to find them?

The pool of people you care about is going to shift over time.

The other mistake I think people make is talking to who's available rather than talking to who they need to talk to.

That's actually one of the most disappointing things about doing user interviews and user feedback, which is why I think... people don't do it. You're going to get negative news about your favorite pet feature most of the time.