값진 교훈 (gab-jin gyo-hoon) – valuable (moral) lesson
This “lesson” isn’t the kind of lesson you attend in schools but more of a moral lesson.
But technically, you can take away a “valuable moral lesson” from a lecture (like a TED talk), in the sense that you’ve learned something outside of the lecture’s content.
Examples:
지난 여름 휴가 동안 한 잊지 않은 경험이 나타나서 값진 교훈을 얻었어.
During the vacation period last summer, I had a unforgetable experience and I learned a valuable lesson.
어느 행복 모르는 사람들이 역경에서 값진 교훈을 얻어야 돼.
Some people who don’t know what is happiness have to learn a valuable lesson from hardships.