In this section of the book, Hannah goes onto explaining how Zach tipped her off by taking her compliment notes. In their class, they have bags with the students names. If you had anything to compliment the students about, you would write it on a paper and put it in their bag. The problem was that for a while, Hannah had not been receiving any compliments. She had no clue why she hadn't gotten any, since she would get them all the time a while ago. Hannah decides to take things into her own hands and figure out why this is happening. She soon finds out that at the end of class, Zach would pretend to give Hannah a note; but really he was taking them all.
Maybe it didn't seem like a big deal to you, Zach. But now, I hope you understand. My world was collapsing. I needed those notes. I needed any hope these letters might have offered.
This is a significant part in the book because this is where everything is falling in on Hannah and she is now realizing it. In this section, Hannah tells us that in her Peer Communications class; is the first place she started thinking about suicide.