Overestimating the intensity or duration of emotional reactions to future events.
Leads to poor decision-making about future commitments, overinvestment in single outcomes, and inadequate emotional preparation.
People consistently overestimate both how good they'll feel about positive events and how bad they'll feel about negative ones, and how long these feelings will last.
"Your confidence in your own rationality is inversely proportional to your actual rationality. Ironic, isn't it?"