I think it's about the flow e.g. you're in the flow if you can arrange the whole thing in your head(i.e. developing a habit of thinking in a language), you don't have to look to manuals and most importantly if you can reflect upon the language (at least I've observed this pattern among great hackers I admire). You can do amazing things if you achieve the experiential-mode but as I've observed people that I admire it's the reflective-mode that takes you to the next level.
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I think it's about the flow e.g. you're in the flow if you can arrange the whole thing in your head(i.e. developing a habit of thinking in a language), you don't have to look to manuals and most importantly if you can reflect upon the language (at least I've observed this pattern among great hackers I admire). You can do amazing things if you achieve the experiential-mode but as I've observed people that I admire it's the reflective-mode that takes you to the next level.