You will never know everything. There's too much information out there and not enough time to learn it all. What this means is, sometimes we're wrong because we just don't know all of the answers. And that's fine—it's 100% OK to be wrong!
If you're wrong about something, it's not a big deal. It's an opportunity to do better, to learn something new, and grow. Your teammate will know more about a topic than you, just like you know more about a topic than them. That's the great thing about working on a team! You can teach each other about these topics, and your skills will probably compliment one another to the benefit of everyone.
My brain is pretty tired today and words are hard, so I'd like to open the comments for people to share their favorite resources for learning new things. Where do you like to learn about productivity? What books do you recommend on philosophy or ethics? Who's your favorite author of UI/UX books? Whatever you got, I want to hear it. :)
This series of posts document a high-level process to use when planning a modern web application, from project organization, collaboration considerations and tooling choices during development, all the way through deployment and performance strategies.