Seneca identifies one of the most common sources of human suffering - our tendency to create elaborate mental scenarios of future disaster that never actually occur. Our imagination, designed to help us prepare for challenges, often becomes a source of torment as we mentally rehearse worst-case scenarios repeatedly. The actual experience of difficulty is usually less overwhelming than our fearful anticipation of it. We live through hardships multiple times - once in worried imagination and again (if at all) in reality. By recognizing this pattern, we can reduce much unnecessary suffering by staying grounded in present facts rather than future fears. The mind's capacity for vivid imagination becomes a blessing rather than a curse when properly directed.