I liked it a lot! The tension was unbearable as he listened to the ways each person had treated this girl badly, and so much of it was stuff that I could remember from school. I don't think teenagers realize what they perceive as common behavior--scraping the nerd off their shoes--is brutally damaging (and in the case of some, they don't really care, admittedly).
I think it makes us think a bit more about the actions we take-both positive and negative-toward others. The little things we don't think matter...absolutely do.
I don't know if it was life-impacting, but it really woke me up to how easy it is for someone to fall through the cracks into depression and farther. It really was unforgetable.