What was the best lesson and the worst lesson you’ve learned?

When I was a high school student, my korean teacher read aloud his note that had =was written on textbook years ago. He only bring that book foxed and worn-out, and only read it. we just taked = took dictation note his reading. so our learning achievement was very low. That was the worst lesson.
On the other hand, the best lesson I’ve learned was my graduate school class. At that time, the professor of that class had a excellent personality. so we respect him, his teaching method was also best. He had asked us some questions that prompt our thinking. Thanks to him, we had = have  thought = learned continuously, and had a heated discussion. Though that class, I realized it is important that thinking is shared thinking and discuss grow me up.
Anyway, because, I have learned a number of great lessons in each lessons for better or worse. Though bad lesson I learn what is wrong, and how I do. All experiences have affected me, and grown me. I want to make a evaluate all are good to me.