I also wonder if there's a subtle psychological effect here: You, in particular, sound like you know a whole lot about at least a few things. But, that means wh

I also wonder if there's a subtle psychological effect here: You, in particular, sound like you know a whole lot about at least a few things. But, that means when you tackle something new, the "know a lot about it" bar is set really high. You're already an expert at X, so you know how hard it is to become an expect at something, and when you start learning Y, it's clear how hard you have to work in order to get close to the same magnitude as your knowledge of X. As a result, it feels like it "takes longer" to learn stuff. But maybe it's just more stuff? I think I heard this argument first made by Adam Savage (of Mythbusters fame).