The Stoic emperor isn't simply saying that peace of mind makes life pleasanter—he's making a mathematical claim about reality itself. If the universe operates by reason and order, then a mind aligned with that same rational principle becomes, in a sense, a microcosm of the whole, vibrating at the same frequency as existence. When you're at war with yourself (chasing contradictory desires, ignoring what you truly know to be right), you're literally working against the grain of how things are. Watch someone caught between ambition and integrity, constantly second-guessing their choices: they exhaust themselves, and nothing they accomplish feels quite right—not because the world is punishing them, but because they've split themselves in two.