Thoughts after reading long overdue

I just finished this article named “long overdue”, I felt I have so many commands with the writer. There is a important sentence in this article is “Think of something you said. Now write what you wish you had said.”
That was a winter 4 years ago, my girlfriend said she wanna separate with me. At that time, I said nothing, we just faced to face. She said I have to go, and then she disappeared in the end of the street. At that time, I think I should say something like “I highly value our love, but if you really want to separate, I.….” Maybe I could save our love. I repented having said nothing.
But sometimes, silence means more than words in some situations. That was my second finally exam in Wuhan university. My classmate sat beside me who was the grandson of the university master. When the exam almost finished, he got a peek on my paper. The teacher saw that and said I was cheating. I was so angry, cause I did nothing. And the teacher was saying some bad words all the time. I got angrier, and said to him “why he was cheating, but you said I was cheating, because I always miss your class? because he is the university master’s grandson? You are a snob.” I rend the test paper into pieces and went out the classroom. I was repented of that. If I didn’t like that, perhaps I would still in that university which was the fifth in China.
In my opinion, to learn how to treat the things in different situation is a lesson we have to study in our lives.