We're Kimberly and Kyle. She's part of me, so I can't be me without her.”
-- Kyle (chapter 1)

Importance: Kimberly has just told Kyle she wants to break up because she wants to know what kind of person she is without him.

The world can keep going on if it wants to. I won't.”
-- Kyle (chapter 4)

Importance: Kyle is in the depths of his grief over Kimberly's death. At this point, he feels there is no way for him to move forward without her.

I guess, if I think about it, I don't have much of a plan for myself. More of a plan for us.”
-- Kyle (chapter 6)

Importance: Kyle is facing the reality of his future now that Kimberly is dead. He realizes he has no idea what he wants to do for himself. Figuring that out is a major step in his own emerging maturity.

I'm struck again with the feeling that I shouldn't be here.”
-- Kyle (chapter 10)

Importance: Kyle's feeling...