If you can't get in touch with your customers to get feedback at the earliest stage, how are you going to get them to use your product? And if you don't want to talk to customers because you're ashamed of the prototype or you want to show them something 'perfect', you'll never talk to them at all.
adora also spoke at the female founders conference (https://www.youtube.com/watch?v=7eP3-ra8nZY) and her story about her and her brother's persistence in systematically climbing the learning curve of product/market fit was one of the most memorable. you can tell that she was speaking from real, hard-earned experience for each of the lessons she related in this lecture.
and i love that she threw in a basketball reference, even though you don't usually just throw the ball around. =)
I'm expecting much of this course to repeat things we already know from reading PG's essays and other blogs, condensed and clarified. That's not a bad thing, as you said it's good to keep it in our heads. And I think there will be new nuggets of wisdom embedded in the stuff we "already know".
Underestimating this initial process, taking it for granted, we create the perfect environment to trick ourselves in not doing it. We might tell ourselves that our product is a SaaS for a very specific crown that we can only find online, and there is no street fair or postal office where we can find them. We might tell ourselves that a $100 Facebook Ads campaign is good for testing our assumptions. Or that is not necessary to get really immersed on our industry, because we already know what is wrong and how to solve.
These are all little lies that convince ourselves that our particular context is different. Sure it is. Sure you might not find your customers on the streets, but that is no excuse to not talk online to your customers, be constant presence on a forum, and arrange meetings with those who happens to be on your city.
Most of advice for startups out there are for those who already have some traction, a few employees. So people might skip the skills and attitude necessary to go from 0 to 100 users or customers. This is the perfect lecture for this crowd.