Anger or pride is drafting the battle plan.

The brake at the end of a book about winning. After thirteen chapters of deception, manipulation, and fire, the closing moral is restraint: "Move not unless you see an advantage; use not your troops unless there is something to be gained; fight not unless the position is critical." Emotions are reversible; consequences are not. That asymmetry is the whole argument: anger passes, kingdoms don't return. So "the enlightened ruler is heedful and the good general full of caution," and "this is the way to keep a country at peace and an army intact." The treatise bends back to its first sentence, that war is "a matter of life and death, a road either to safety or to ruin," and therefore never an instrument of mood.