Well, I liked it. I had never heard of BEM before, either, so I'll definitely take a look at that. What gets me about CSS is that, in spite of having used it now for about 20 years, I still don't have an intuitive feel for it. With everything else I work with, I start out with an experimental approach: if I change this, I see this, if I change that, I see this other thing; after usually a few weeks of experimentation, I develop an intuition for it so that I can usually predict what it's going to do before I have to see it do it (admittedly it took more than a few weeks to get to that point with Lisp and assembler). CSS, though, just seems to deny intuition; even after reading the O'Reilly "CSS: The Definitive Guide" book, I don't have the faintest clue what my CSS is going to do until I try it out.
Hear, hear! Working exclusively in scss, maintaining orderliness and decent discipline, and having - like you - been at it for close on twenty years, I still keep a constant wary eye on my output screen, I still get regular surprises there, I still rely on the browser dev-tools, and I sorely miss the 3d representations they used to have, at least in Firefox.
I have learned to simply accept css for what it is: An unholy legacy kludge we have to live with. Just don't let's speculate on the millions and millions of wasted man-hours over the years.
Welcome to css-tricks.com [0], where you will learn all the current trends. I am a regular reader for things just like this. Where you just want to know what's new and where things are going. Plus they have an amazing stockpile of CSS examples.