I've only skimmed the top of this so far but the bit about AC vs DC rings true for me. I'm just getting into electronics and I just couldn't understand what capacitors did. I watched all the water membrane videos and it all made sense, but what could it do? It clicked when I realised I had until this point separated all electricity into AC and DC and in my mind my electronics project was DC! I was confused because a capacitor seems like an open circuit, which it is (at DC). I didn't even allow the possibility of considering that there is AC on my circuit. But that's the entire point of electronics. Transistors and other components allow you to switch current on and off, hence AC.

Now it has clicked I intuitively understand how things like bypass capacitors work. But I don't think I could explain it well enough to teach it. It seems like it it doesn't click for you you'll never be able to do electronics.

I noticed in The Art of Electronics they don't capitalise ac and dc. I wonder if that is to escape the popular ideas of the capitalised AC and DC? I looked but couldn't find an explanation in the book.