It made no difference at all but he couldn't help seeing what he saw. Things different or things not right or out of place or in place when they shouldn't be or not in sync with the words that came with them.
-- Narrator (Chapter One)

Importance: This quote takes place during the first time Isaiah shows off his detective skills. The narrator informs us that Isaiah has no choice but to view the world as a series of mysteries to be solved. It is the way he is wired and built.

This album right here, Don Kulluminati? It’s a classic, didn’t come out ‘til after Tupac was dead and gone”
-- Dodson (Chapter 3)

Importance: Dodson says this to Isaiah when they are on their way to Calvin's mansion for the first time. It is the case-breaker, although the characters do not realize this until the very end of the novel.

He hated threats. Some asshole like...
-- Narrator (Chapter 3)