Assuming you already have a fairly well-defined set of values and a personal philosophy, the next most useful genre by far is psychology. It's not even a close

Assuming you already have a fairly well-defined set of values and a personal philosophy, the next most useful genre by far is psychology. It's not even a close contest. As for self-help/attitude improvement, it's only useless if you don't already know what science suggests are good habits and behaviors. From there, it's the process of integrating those into your life that becomes critical. Speaking as someone who chronically lacked discipline, which then translated into a lot of mistakes, among the most important things a person can understand is the value of positive habits and behaviors, compounded over a long time period. Habits and behaviors are what drive wellbeing across a variety of different dimensions: diet, exercise, learning, growth, experience, socialization, etc. They are the principal foundation of a happy life, and most people never even come close to appreciating their full importance. All that said, I'll be the first to admit that the self-help genre is typically more about dopamine hits and quick sales than real results.