Judgment and judgmental anger
Judgment is one of those words that sounds scary, and it is scary, but it's not necessarily a bad thing. Judgment is merely criticism; it is the human ability to try and find justice. Judgment is about making things better, by systematically fixing problems, but that's not the only part of judgment. What happens when instead of fighting for truth and order, a person uses their judgmental attitudes to become angry that they aren't getting what they want? Reef shows us plain and clear. By literally "Throwing the first stone" as the title suggests, we see that Reef's character flaw is that he allows his emotions to make him violent. Why? Because he is angry that he isn't getting what he wants, and he wants to judge whoever is responsible for that. If no one in particular is responsible for it, he'll be violent against anyone, even Leeza Hemming, it seems.
Intimacy, friendship, and approval
Reef is a disenfranchised, somewhat grumpy guy who wants to fit in, and he does have some buddies that he really enjoys, but as soon as he meets Leeza, he considers their relationship in terms of what she will think of him. Reef wants Leeza to like him because a friendship with an attractive girl could help him to work through his feelings of self-disapproval. In other words, Reef is craving human intimacy, affection, and approval. Why doesn't he really get it? Because he became violent in his grumpy anger.
Time and karma
The book is a picture of a boy learning about his karma. Simply put, he learns that regardless of how he feels emotionally about his actions, he is perfectly responsible for his wrong-doings, which comes with a huge plus side: If he adjusts his sense of entitlement and learns to think through his decisions more, he can manage to create a meaningful life for himself. Just to underscore this theme, notice that the beginning of the novel sees Reef and his friends complaining that the city government is shutting down their favorite hang-out spot. This means that it's change that they are angry about, but that's what time is all about. Things change.
