I wish I had more time to get better with emacs. I use it all the time and when I see things like this it makes me love emacs and hate that I don't take advantage of how deep it is.
I also find it useful to keep a short file of features I want to learn and features (1 or 2) I'm currently learning (trying to use as much as possible even if it slows me down a bit so that they'll stick in my mind).
One thing I'd really like to do is to make a massive index of emacs-lisp code on github. That would be a fantastic resource.