Everyone wants you to be happy: Self-help books dish out advice on how to stop worrying, boost happiness, and banish negative thoughts; bosses want to see smiling enthusiasm in the workplace; and the only way to respond to “how are you?” is with a joyful “great!” But according to Svend Brinkmann, a psychology professor at Denmark’s Aalborg University, the culture of positivity has a dark side.

Happiness is simply not the appropriate response to many situations in life, says Brinkmann, whose Danish bestseller Stand Firm: Resisting the Self-Improvement Craze is published in English by international publisher Polity this month. Even worse, faking it can leave us emotionally stunted.

“I believe our thoughts and emotions should mirror the world. When something bad happens, we should be allowed to have negative thoughts and feelings about it because that’s how we understand the world,” he says.

“Life is wonderful from time to time, but it’s also tragic. People die in our lives, we lose them, if we have only been accustomed to being allowed to have positive thoughts, then these realities can strike us even more intensely when they happen—and they will happen.”

There’s nothing wrong with those who have a naturally sunny disposition or who enjoy the odd self-help book, says Brinkmann. The problem is when happiness becomes a requisite. In the workplace, for example, where performance reviews often insist on focusing on positive growth rather than genuine difficulties, demanding displays of happiness is “almost totalitarian.” Brinkmann likens insistence on employee happiness to “thought control.”

In the US, mandatory happiness became the subject of an official workplace ruling against T-Mobile in May 2016, where the National Labor Review Board determined that employers cannot force employees to be consistently cheery. All the same, many companies spend huge sums of money trying to ensure employee happiness, and not out of altruism. “When you engage with people and you work in teams, then these personality traits become much more important. That’s why we put much more emphasis on them, because we want to exploit humans and their emotional lives,” says Brinkmann. “I think this is a dark side of positivity. Our feelings tend to become commodities and that means we’re very easily alienated from our feelings.”

Mandatory happiness isn’t simply a concern in the workplace. While it makes sense to give a ritualistic “good, thanks” when someone asks how you are in passing, there’s a risk that our positive public faces are increasingly dominating social spheres. After all, while a witty, vivacious atmosphere can be enjoyable, polite positivity shouldn’t prohibit discussion of traumas and crises with close friends.

Tied up in the pressure to be happy is, of course, the self-help craze. Self-help books that purport to teach people how to find happiness could encourage a harmful perspective on emotions, says Brinkmann. The underlying idea that anyone can make herself feel happy implies that unhappy people are to blame for their own misfortune.

Ultimately, negative emotions play an important and healthy role in how we understand and react to the world. Guilt and shame are essential to a sense of morality. Anger is a legitimate response to injustice. Sadness helps us process tragedy. And happiness is great too. Just not all the time.