[AriseAndPass]

I think your reply reinforces a conclusion I drew from the OP's reply - that the common thread here is to work on _building_ things that exist at lower levels of abstraction, rather than just knowing how to use them as a black box. And in building things, I guess you learn the ins and outs of how they work, which makes you better at using them?

Thanks for the examples. I'd never even think of being able to build my own programming language, or clone of Flask - which I guess is the point, I shouldn't treat these things like black boxes :)

[eatonphil]

Yeah by building stuff you come to understand that all abstractions are arbitrary but you also come to understand why previous projects picked the abstractions they did. So it helps even just as a user, you don't have to be building frameworks, languages, databases professionally to benefit here.