Who is the narrator, can she or he read minds, and, more importantly, can we trust her or him?
First Person (Central Narrator)
The entirety of What Happened to Goodbye is told from Mclean Sweet's perspective, which makes sense—after all, this is her story. More than that though, because Mclean is a pretty closed-off person who prides herself on not making strong attachments when she moves to a new place, it's super helpful for the reader to get her innermost thoughts as events occur—she's certainly not going to share her feelings out loud with other characters.
Through Mclean's perspective, we get to see her feelings on getting close to other people, her ambivalence toward her mother, and even her fear of leaving her father all by himself. It's tricky emotional terrain at times, but Mclean recounts it clearly and honestly to readers as she goes.