Elon Musk’s chaotic leadership of Twitter has brought us to a clarifying moment in how we think about work, leadership, and peak performance. On the one hand, his burnout-fueled decision-making seems like a regression—a step, or many steps, backwards, given what we know about the connection between human energy and decision-making. But on the other hand, he’s showing us the vivid results of that backward-looking model: total chaos. Musk’s second month at Twitter has been an extension of his master class in how not to make decisions. And the lesson is clear: we only have so much cognitive energy—and what we choose to spend it on, and how we renew it, really matters.

Last week began with Musk installing mattresses at Twitter’s offices in San Franc…