This document summarizes the key differences between two personality types that are present in all military populations: Cluster B and Cluster C. Cluster B personalities thrive in conflict situations due to their adventurous, daring and decisive nature, but struggle in peacetime garrison settings. Cluster C personalities excel in peacetime through their dependability, conscientiousness and adherence to rules/procedures, but have difficulty with risk-taking and decision-making under the ambiguity of war. Over time, as a military shifts to a long period of peace, the leadership becomes dominated by Cluster C personalities, leaving the force unbalanced and initially less effective when the next conflict arises due to inadequate risk-taking and decisiveness.