I think the one thing that stuck with me, personally, is the issues Dropbox had in the early days (TC 50 tech issues) and that it took six months to get Aston on board. From what I understand, pre-YC was not easy for Drew either.
As a stubbornly impatient person, this has to be hands-down the hardest part of building a startup. You're running an endless marathon as if your life depended on it, and you have to stop at the sidelines and calmly ask people if they'll run with you. And then be okay if they don't - because the course will change, and as it does it will become more attractive to different sets of people. You might see the finish line, but you have to understand that not everybody will see it the same way you do.
The thing that I'd add here is that Aston kind of downplays how important having a business model is as an employee / founder (at least per Drew joking around about pricing). I don't think he did this intentionally, but generally we're over saturated with these ideas that you just need a product people love. These stories inspire technical founders, but having a defensible business is something you should think about sooner rather than later. Not everybody can be a Dropbox, so learn as much as possible about every aspect of what your company can and will be, learn how to communicate that, and stack the deck in your favor. It's an ongoing process and I certainly am not one to claim mastery (far from it), but as somebody who's in the weeds it's the perspective I have.