Ask HN: When did your mentality “click”?

Sometime during my graduate studies, I took a group of classes that were mostly seminars, and something remarkable happened over the course of three months. I stopped caring about exams and started caring about the applicability of what I was learning.

I discovered I was able to absorb and communicate knowledge with fresh clarity. I stuttered and mumbled less. My curiosity for many things related (computational science, engineering) and unrelated (macroeconomics, political systems) suddenly opened up. I started reading non-fiction voraciously, and initiated a virtuous cycle of knowledge assimilation and application. Of course, I can only analyze these events in hindsight as being reformative.

Do you recall such a transformation in your life, and what triggered it?