I was always thirsty for knowledge.

But you retain “enough” by understanding basic concepts* for later, if needed, to learn more & even get a proper skill out of it.

But it’s pointless to learn stuff you don’t get just got grades. Well, unless to train memory, but there are better ways for that.

(*depth of basic concepts can be pretty significant, I don’t mean that just as a superficial knowledge of a general subject)