We're in class, talking about how dynamic scope works: when you pass more than one argument to your closure, whatever else you pass is going to follow the dynamic flow of your computation rather than the rules of lexical scope. We're told that this idea is going to become important later, when we talk about other stuff.
All of a sudden, I realize that by "other stuff" we mean "continuations". I ask about this. "Yes."
A week later, we're in class, talking about continuation-passing style. All of a sudden, an analogy occurs to me: Continuation-passing style is to accumulator-passing style as accumulator-passing style is to naive recursion. I ask about this. "Yes."
I get it, I get it! I understand! I'm so excited!