A close friend of mine in the late 1980s was a serious wizard. He saw me struggling with something and said "Why don't you use Emacs?" And I was like, What's Emacs?
"Every key calls a function. Letter keys are bound to the function that inserts that letter, but you can bind any key to any function. And you can write functions to do whatever you want."
Immediately I saw the essence of Emacs.