The Stoics made a claim that is, by the standards of most ethical traditions, radical: virtue — the quality of your character — is the only genuine good. Everything else — health, wealth, reputation, pleasure, professional achievement — is a preferred indifferent: something worth pursuing under normal circumstances, but not something whose achievement constitutes genuine wellbeing.
This claim is difficult to accept. It runs counter to most of what our culture tells us about what matters. It challenges the assumption that success is genuinely good and failure is genuinely bad. It suggests that the person who fails with integrity has, in the most important sense, done better than the person who succeeds without it.
But properly understood, this claim is not a counsel of indifference or mediocrity. It is one of the most liberating ideas in all of philosophy — and one of the most practically useful for anyone navigating a demanding life.