I hesitate to say this is a thriller even though it's partially about a murderer. It's more of a character study of the dissociation brought on by a middle class lifestyle. That's how I interpreted the use of the "this is" throughout the book. Whenever it drops away a bit is when Annie is more present, usually at swim meets when she's near ... Paul? Whoever the husband of Chris is with the ponytail. Although not all of the novel is narrated by Annie (or narrated from her perspective in 2nd person) most of it is. And she's definitely dissociating a lot of the time. Aware enough to realize her husband never actually talks to her, but not in herself enough to speak up or insist on being spoken to. Things like that. It's a slower way to read a novel, from that perspective, but a worthy and I think mostly successful exercise.