You have an old house and everything is a bit outdated, but you're satisfied. You add a room air conditioner during one particularly hot summer. A few years later, when you have more money, you decide to add a central air-conditioning system. But you don't remove that room unit in the bedroom — why would you? It might come in handy and it's already there, bolted to the wall. Then a few years later, you have a catastrophic plumbing problem — pipes burst in the walls. The plumbers need to break open the walls and run new pipes, but your central air-conditioning system is now in the way, where some of their pipes would ideally go. So they run the pipes through the attic, the long way around. This works fine until one particularly cold winter when your uninsulated attic causes your pipes to freeze. These pipes wouldn't have frozen if you had run them through the walls, which you couldn't do because of the central air-conditioning. If you had planned all this from the start, you would have done things differently, but you didn't — you added things one thing at a time, as and when you needed them.

In the short run — the cyclical relationship — GDP and happiness go up and down together. During the Great Recession, for example, happiness in the United States collapsed as the economy contracted and then recovered as GDP turned upward. But over the long run — the trend relationship — countries with more rapid economic growth do not experience a greater increase in happiness. Indeed, in the United States, the trend in happiness has been flat for over seven decades, a period in which real GDP per capita more than tripled. Even more spectacular, China's life satisfaction was no higher in 2010 than in 1990, despite an unprecedented fourfold multiplication of real GDP per capita in only two decades. There are some scholars who claim to find that happiness trends upward along with GDP, but they are confusing the positive short-term relationship with the nil long-term relationship. The absence of a long-term relationship suggests that it is time to reconsider the long-held belief that economic growth increases human well-being.

Just the other day, a dear friend of mine — a retired brigadier — was narrating the story of how a line he heard many, many years ago impacted him deeply and shaped his life. It was his first week in the army. It was a Sunday morning. The task ahead was rather simple. They had to run ten miles. My friend recalls having started enthusiastically, and then quickly tiring out. After running half the distance, he felt he couldn't continue any longer. He felt his legs would fold up and he'd collapse. And just as he was about to give up and stop, he heard his commanding officer say to him, ‘Come on, young man. Until now you've been running with your legs. Now run with your mind!' Those words seemed to work like magic. While my friend doesn't quite recall what happened thereafter, all he remembers is that he kept running. He finished the entire ten-mile run. And to this day, he often hears the officer's words echoing in his mind.

In Thinking, Fast and Slow, Nobel Prize-winning psychologist Daniel Kahneman points out an emotional benefit of motivated reasoning: resilience. It's easier to bounce back from a failure if you can blame it on anyone but yourself. He uses the example of a door-to-door salesperson, a job that involves long strings of rejection: "When one has just had a door slammed in one's face by an angry homemaker, the thought that ‘she was an awful woman' is clearly superior to ‘I am an inept salesperson.'" But are those really our only two options? We could instead tell ourselves, "Yes, I screwed up that sale. But everyone makes mistakes." Or "Yes, I screwed up that sale. Still, I'm improving — I used to get doors slammed in my face every day, and now it only happens every week!" Surely we can find a way to bounce back from our setbacks that doesn't require us to blame them on other people — an honest coping strategy.

Joseph Schumpeter once said that an invention that is not widely used is irrelevant to human affairs. There are thousands of ingenious and admirable inventions that were neither carried out in large scale nor used by millions of people to change the world. Hero of Alexandria in the first century produced a steam engine by jet action, but it was treated as a curiosity and did not lead to benefits for society. Leonardo da Vinci invented a number of flying machines, but there is no record that they were ever built to change transportation or warfare. Crawford Long of Georgia actually used ether for anesthesia in surgery a few years before William Morton in Massachusetts, but Long did not publish his results and had no influence in subsequent medical history. Out of the many thousands of inventions in history, only a few were able to travel the long and difficult path from discovery to development, to be manufactured on a large scale, and to be sold widely in the marketplace, and effect significant change in the world.

My friend Mary Pat has a smart and capable 16-year-old grandson. He was not doing his best in school, much to his parents' dismay. One day he asked his mother if he could dye his light brown hair. "What color?" she asked. "Bright blue!" he said with enthusiasm. Sensing an opportunity here, Mom replied only with a number. "3.8." Shorthand for, "If you want blue hair you must earn a 3.8 grade point average in school. Otherwise I will say NO to this crazy color!" Mary Pat saw her grandson a few months later sporting bright yellow hair. "I thought you were going to dye your hair blue," she said quizzically. Greg's answer was short: "3.5." When Greg and his mom realized a 3.8 grade point average wasn't going to happen they adjusted his goal to one more attainable, and everyone was happy. Goals motivate only when they are attainable. Sometimes they need to change to fit the individual and the circumstances.