Enormous subjects are best approached in thin, deep slices. I discovered this when first learning how to program. The textbooks never worked; it all only started to click when I started to do little projects for myself. The project wasn’t just motivation but an organizing principle, a magnet to arrange the random iron filings I picked up along the way. I’d care to learn about some abstract concept, like “memoization,” because I needed it to solve my problem; and these concepts would lose their abstractness in the light of my example.
I love the phrase "thin deep slices" for learning. This is also in Lines. This page exists so I can come back to it later, I want to think about this more.