Cheer up. Feel better. Don’t worry, be happy. Smile more. As an emotion, cheerfulness has astonishing range. At its best, it’s a style of kindness that we extend to others, a salve during times of trouble, and a way of coping with trauma and despair. At its worst, cheer can be breezily dishonest, an on-demand feeling that we can project to get what we want. It can also be a burden, especially for women and people of color, many of whom feel pressure to be constantly upbeat.

When it comes to moving votes and consuming public attention, the strongest and most negative emotions come to mind: anger, hatred, fear, resentment. But Timothy Hampton’s lively new cultural history of cheerfulness is a convincing argument that modest feelings matter too—even (or especially) as democracy shrivels and the planet overheats. Cheer, which Hampton describes as a “temporary lightness, a moderate uptick in mood,” turns out to have a captivating backstory; it’s helped people build communities, muddle through, and get ahead since at least the Middle Ages.

Hampton would like us to see cheerfulness as a rich moral sentiment, not just a fleeting psychological gimmick. Yet what he has really done, brilliantly if inadvertently, is reveal cheer’s shadow side: the way it lures us into valuing surfaces over substance, the peculiar degree to which it can be conjured and wielded at will, and, ultimately, how it so handily serves and protects those with power.

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Cheer, according to Hampton, isn’t what it used to be. The cheap version we know today, a ploy for selling beer and breakfast cereal and political candidates, is the result of mass consumerism. In his telling, “modern marketing culture” ruined cheerfulness and remade it into a flimsy commodity. Yet cheer was once an emotion with genuine spiritual meaning as well as intellectual heft, Hampton suggests, gently but decisively shaping the history of Western modernity.

When cheer first made its English-language appearance at some point in the 14th century, however, it had not yet acquired these powers. From the Old French word chiere (and possibly the Spanish cara), it originally meant “face” or “countenance,” the visage or impression one offers to the world. In this neutral sense, cheer typically needed an adjective to accompany it. In Geoffrey Chaucer’s Canterbury Tales, for instance, knights were described as kneeling with “humble chere” or galloping into combat with “hardy cheare and face.”

During the religious tumult of the 16th and 17th centuries, cheerfulness took on a more positive gloss. For Protestant reformers such as John Calvin, bright positivity became a signal of Christian charity, virtue, and identity. Over time, cheer became a secular good more than a spiritual one. One powerful force transforming European political and intellectual life in the early modern period, after all, was sociability: gathering in salons and coffeehouses to conduct business and discuss bold new ideas about what was true and who should rule. A light demeanor and upbeat personality made all this easier and more enjoyable. As the Enlightenment philosopher David Hume explained, “true wisdom” was found in the “cheerful discourses” of light conversation, rather than in “the formal reasoning of the schools.” Cheer powered the growth of capitalism, too, by boosting productivity (the economist Adam Smith identified a virtuous circle in which higher wages led to cheerfulness and thus more diligent work) and fueling the consumer economy. By the 19th century, cheerfulness was a marker of social mobility: In the realist novels of writers such as Balzac and Stendhal, for instance, cheer is associated with lower-class provincial men on the make, happily hustling and ascendant in a new capitalist world.

Of course, the history of anything that human beings value is also, inescapably, a story of attempts to control it. Cheer has always felt more under our command than other feelings, treated as an emotion that can be deliberately triggered. Today, you might use balloons or a bouquet of flowers. In 1561, a Dutch physician advised that “good cheere” could be made via “kissing … dauncinge, Wyne, and singing.” One 17th-century medical handbook told its readers to mix a “Powder to Create Cheerfulness” by combining ingredients such as saffron, ambergris, and shavings of bone from a stag’s heart.

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This manipulative instinct has been especially obvious in the United States, a country that has pioneered the expression and commodification of cheerfulness in too many ways to count, including cheerleaders, Cheerios (invented in the 1940s and marketed with the slogan “He’s feeling his Cheery-oats!”), and the smiley-face icon. As American economic and geopolitical dominance swelled in the 20th century, a new wave of entrepreneurs and spiritual advisers told millions of readers that achieving worldly success was a matter of choosing to be cheerful. In the 1930s, the most famous of these figures was Dale Carnegie, whose best-selling handbook How to Win Friends and Influence People stressed the benefits of good cheer for business advancement. In 1952, a Protestant minister named Norman Peale published The Power of Positive Thinking, which argued that health and wealth were the result of optimism and a cheerful outlook. (One of Peale’s most infamous fans? Donald Trump.)

This self-determined vision of cheerfulness is still minting gigantic profits for the American self-help industry. See: the Rhonda Byrne best seller The Secret (remember “manifesting”?) and the cryptic sermons of Marianne Williamson, who has suggested that disease and despair are illusions that can be overcome by choosing more positive feelings. Feeling spontaneously, genuinely cheerful no longer matters—if it ever did. What’s crucial is that you put on a convincing show, for others as much as for yourself. As Hampton explains, modern life has stripped away cheer’s authenticity and made it fully performative: “To act cheerful is what it means to be cheerful.”

It is always comforting to think that modernity has corrupted us: our morals and our manners, our children and our politics, our intellectual lives and our natural environments. This means that there was once a golden age, something for us to recover. Hampton offers this kind of degeneration story about cheerfulness. He proposes that cheer has decayed from a substantive sentiment into the tacky and shallow feeling we’re familiar with today. American-style manufactured cheer is merely “a distant echo” of an “earlier moment,” he explains, “now largely stripped of its spiritual underpinnings.”

But Hampton’s own book reveals that cheerfulness was never really so pure. From the start, cheer’s earnest and best self has coexisted with its phonier twin. Medieval French nobles realized that by responding to hostile neighbors and potential threats by putting on a “good face” (bonne chère), they could avoid violent feuds. Renaissance courtiers learned from influential texts such as the Italian diplomat Baldassare Castiglione’s The Book of the Courtier that a chipper personality could grease the skids of their social or political ambitions. And many popular etiquette guides in the 18th century advised young women to carefully perform “constant cheerfulness,” as one called it, a kind of “innocent deceit” that would help them succeed in the world of men and manners. Counterfeit cheer, in other words, is not so modern an affliction as Hampton would like us to think.

Emotions are usually defined by their ungovernability, experienced as forces that wash over us and challenge our sense of agency. That quality is what makes most seem authentic and trustworthy to us. Fake anger or love feels like a betrayal. But fake cheer? It’s hard to say how it’s so different from the real thing. Cheer has always been perched on a knife’s edge between truth and falsity, making it especially vulnerable to political manipulation and abuse.

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Indeed, powerful interests have long used cheerfulness to counsel complacency and forestall action. At the turn of the 20th century, for instance, America’s striving middle classes and exhausted workers were instructed by best-selling inspirational books like Cheerfulness as a Life Power (1899) to be upbeat at work instead of complaining. Because cheer “lengthens the life of human machinery,” one writer explained, it would make everyone’s work easier and more efficient. Much later, Ronald Reagan (appropriately, a cheerleader in college) found in the rhetoric of buoyant national optimism a handy way to defang social democracy while boosting the neoliberal project. During his campaign for president, he tried to convince voters that success was owed largely to a cheerful mindset rather than government support or social conditions. Even today, America’s political establishment prefers its candidates to be “happy warriors” instead of furious crusaders, and frets more about the pessimistic tone of activists than the substance of the demands they make.

Nothing about this darker history means that cheer is anti-democratic, or that optimism is politically naive. Far from it. Social movements, as most organizers and activists will tell you, depend on it to make the hard work pleasurable. But it’s not as anodyne as we might think. Cheerfulness is a political emotion like any other, mercenary and vital and able to make worlds as well as break them. Hampton would like us to harness cheer’s overlooked ability to “transform the moral self.” Yet the greatest risk we face as democratic citizens may be not the neglect of cheerfulness, but rather the reverse: that we trust in it too easily.