The Greeks called it eudaimonia, which sounds like a cleaning product but which actually means “the fullest and purest expression of you in your most elevated state.” Their idea was that each of us had a spirit, or daimon, that embodied our greatest and most unique possibilities—our natural strengths or talents—and that the state we should all seek was one where, because of the happy intersection of our role, our skills, our team, and our context, we turned these possibilities into contribution, and thus liberated our good spirit.

When marketing a product, service, or experience, for example, is it more hedonic or more utilitarian? Are people buying it for pleasure or enjoyment, or more functional or practical reasons? If it’s more about enjoyment, emotional words like “awesome” and “beautiful” fit really well. Saying a movie is “heartwarming,” a destination is “inspiring,” or a meditation app is “fantastic” not only suggests those things are good but does so in a way that encourages purchase and action.

If the product, service, or experience is more about practical functionality, however, those same positive words may backfire. Less emotional words like “brilliant,” “flawless,” and “perfect” will be more persuasive. Calling a dictation app “brilliant” rather than “awesome,” for example, should encourage purchase and use.

Some psychologists object to the word “happiness” because it can mean anything from a temporary pleasure to an almost mythical sense of eudaimonic purpose that few in reality manage to reach. So in lieu of happiness, more nuanced terms like “well-being,” “wellness,” “thriving,” and “flourishing” have become common in the popular psychological literature. We use those terms in this book. Marc is particularly fond of the terms thriving and flourishing because they refer to an active and constant state of becoming, rather than just a mood. But we still use “happiness” at times for the simple reason that this is how people talk about their lives. Nobody says, “How’s your human flourishing?” We say, “Are you happy?” And it’s how, in casual conversation, we both find ourselves talking about our research as well.

Throughout this book, we’ll be addressing some of the common reasons why people have a hard time finding happiness and satisfaction in life, but there are a couple of general truths that should be acknowledged right off the bat.

The first is this: the good life may be a central concern for most people, but it is not the central concern of most modern societies. Life today is a haze of competing social, political, and cultural priorities, some of which have very little to do with improving people’s lives. The modern world prioritizes many things ahead of the lived experience of human beings.

The second reason is related and even more fundamental: our brains, the most sophisticated and mysterious system in the known universe, often mislead us in our quest for lasting pleasure and satisfaction. We may be capable of extraordinary feats of intellect and creativity, we may have mapped the human genome and walked on the moon, but when it comes to making decisions about our lives, we humans are often bad at knowing what is good for us. Common sense in this area of life is not so sensible. It’s very difficult to figure out what really matters.

These two things—the haze of culture and the mistakes we make in forecasting what will make us happy—are woven together and play a role in our lives every single day. Over the course of a life, they exert significant influence. The culture we live in leads us in particular directions, sometimes without our even noticing, and we follow along, outwardly pretending that we know what we’re doing, but inwardly in a state of low-grade confusion.

Thousands of stories from the Harvard Study show us that the good life is not found by providing ourselves with leisure and ease. Rather, it arises from the act of facing inevitable challenges, and from fully inhabiting the moments of our lives. It appears, quietly, as we learn how to love and how to open ourselves to being loved, as we grow from our experiences, and as we stand in solidarity with others through the inevitable string of joys and adversities in every human life.