Seneca isn't simply warning us against worry—he's identifying a peculiar human talent for manufacturing suffering through anticipation. Most of us assume our pain comes from what's actually happening, but he's pointing out that we often do the bruising ourselves, long before circumstances demand it. When you rehearse a difficult conversation in your head for three days before it happens, practicing your defense and imagining rejections, you're paying the emotional price twice over—once in fiction, once in fact. The stoic wisdom here cuts deeper than "don't worry": it suggests we're often our own cruelest tormentors, not because life is hard, but because we insist on living through our hardships before they arrive.