In the podcast between Spencer Greenberg and Buck Shlegeris, Taking pleasure in being wrong, Buck says:

I think that when you are learning subjects something that you should really be taken your eye out for is the simplest question in the field that you don't know the answer to.

I think a lot of the time people try to learn physics or something and their approach is as quickly as possible to answer hard questions about complicated subjects. And I think that's what I thought was cool when I was younger. They delighted at questions that were at the limit of fanciness that they could possibly answer and it feels to me now that it is a lot more productive to seek out questions that are as simple sounding as possible while still being really hard to answer. Or that still demonstrate that there's something you don't understand about the subject.
[...]
It seems like we should be seeking out these most basic questions in the hope of finding holes in the foundation of our knowledge.

If we apply that approach to applied rationality, what questions do you have that seem to be simple but where you don't know the answer?

Random Attempts at Apllied Rationality