We prefer things in threes (for instance, the protagonist and his or her two other fiends) and have the “Rule of Thirds” because two is not appealing. We are used to focusing primarily on one thing, ourselves, and when presented with a new situation (art, for instance), we need odd numbers; we can’t stand the idea of even numbers because they require a certain amount of equality when in a pair, whereas odd numbers leave an outlier, a single interest for the mind to grasp onto.
Is this why we like odd numbers?
