Optimism is associated with better physical health. Emotions like joy, gratitude, and hope significantly boost our well-being.[8] We need plenty of positive emotions in our portfolio. They should outnumber the negative ones.[9] Yet overweighting our emotional investments with too much positivity brings its own dangers. The imbalance can inhibit

If thinking is for doing, feeling can help us think.[27]

In fact, other research has found that people who thought counterfactually about pivotal moments in their life experienced greater meaning than people who thought explicitly about the meaning of those events.

Regret is a marker of a healthy, maturing mind. It is so fundamental to our development and so critical to proper functioning that, in adults, its absence can signal a grave problem.

more often the performance prevents people from doing the difficult work that produces genuine contentment.

This is one of the central findings on regret: it can deepen persistence, which almost always elevates performance. One of the pioneers in studying counterfactual thinking, Neal Roese, whose research appears throughout these pages and the Notes, used anagrams in one of his earliest and most influential papers. He, too, found that inducing

This process begins with two abilities—two unique capacities of our minds. We can visit the past and the future in our heads.

The very act of contemplating what they hadn’t done previously widened the possibilities of what they could do next and provided a script for future interactions.[4]

Comparison lives at regret’s core. Second, we assess blame. Regret is your own fault, not someone else’s.