Kennedy understood something many miss: that sheer willpower can become a kind of beautiful waste. A marathoner who trains obsessively for a race she doesn't truly want to run, or a person who musters tremendous bravery to pursue someone else's dream, both possess the very qualities the quote mentions—yet they're fundamentally adrift. The real cut of his observation is that effort without a *why* turns virtuous struggle into mere motion, leaving us exhausted but empty. Purpose is the difference between a difficult life and a meaningful one.