The year is 2011. I’m living out of a duffel bag, sleeping on my friends’ couch at night, dishwashing part-time at a pizza parlor because it’s the only work I can find in northern Maine at the end of the summer, and holding in my hands a huge medical bill that I am unable to pay. Oh yeah, and I have pneumonia.

I call my friend, and within two minutes I’m crying. She tells me, “Look on the bright side.” I want to punch her in the face.

Don’t get me wrong. I love my friend, a lot (and I would never actually want to cause her any harm). But when I’m at my worst, I don’t want anybody telling me to act my best. Turns out there’s some science behind my feelings: A look at the research reveals positive thinking isn’t always all it’s cracked up to be. In fact, researchers are asking: What if embracing so-called “negative” states like failure, pessimism, insecurity, and uncertainty actually has a positive outcome [1]?

Positivity, Shmositivity — The Need-to-Know

It’s not until recently that people have started thinking of happiness as something everybody’s entitled to all of the time. And in the headlong pursuit of ever-present positivity, we might be shooting ourselves in the feet. Constant positive thinking, some researchers say, means a person can never relax — because that’s the moment a “negative” thought might squirm its way to the surface. And insisting that “everything works out” offers positive thinkers no back-up plan for when things don’t.

These criticisms are backed by a lot of research. One study found that when people think others expect them not to feel negative emotions, they end up feeling more negative emotions more frequently [2]. Another study found that people with low self-esteem who repeated a positive self-statement (“I’m a lovable person”) ended up feeling worse than people who didn’t repeat the phrase [3]. Some researchers have linked the pressure to “think positive” to personal self-blame (“If I can’t be happy, it must be my fault for not being positive enough”). Denial’s another potential side effect of positive thinking, and some experts even blame the current economic crisis partly on people’s refusal to consider potential negative outcomes.

In fact, says Greatist Expert and psychiatrist Mark Banschick, too much positive thinking can actually be a sign of a mood disorder. People with Bipolar Disorder (or its variations, Bipolar II and Cyclothymia) experience states of excessive positive thinking, called “mania”, that can interfere with their experience of reality and cause them to engage in potentially self-destructive behavior (driving at 120 mph, doing lots of drugs, stealing — because “everything’s great and nothing can hurt me”). Though a typical person doesn’t experience positivity at such a manic level, it is possible for the average Jane or Joe to get swept up by positive feelings, lose their judgment, and do something they wouldn’t normally do.

Positive thinking can also become a way of avoiding necessary action, an issue Banschick sees in many male clients in their early 20s. People might say “everything’s fine” even when it’s not — it’s a way of convincing ourselves we’re doing something about a given situation (a crappy job, a looming deadline, an issue with a partner) without actually... doing anything. “People who use positive thinking as a defense are trying not to feel anxious when they should,” says Banschick. In fact, some amount of anxiety is often necessary for motivating us to act in certain situations. Covering up this anxiety with a cheery face can actually make our situation worse because we’re less likely to address the underlying issue. But the sooner we take action, says Julie Norem, professor of psychology and author of The Positive Power of Negative Thinking, the less likely anxiety is to interfere with whatever it is we’re trying to do.

Defending Pessimism — The Answer/Debate

So some level of negativity might actually be good for us. One study found that people in negative moods can produce better-quality and more persuasive arguments than people in a positive mood. Negative moods can also improve memory and mental accuracy, and other research suggests that negative thinking might prompt us to think more carefully.

In light of these findings, many researchers are criticizing what they see as exaggerated claims from the pro-positivity camp, and standing behind the benefits of negative thinking [4]. Of particular interest is defensive pessimism, a strategy for managing anxiety, says Norem. It involves setting low expectations and being pessimistic about what might happen in a given scenario. Studies find the strategy helps people manage anxiety by mentally planning for the worst (giving people a greater sense of control); it also allows them to perform their best, typically because they work extra hard to ensure that possible negative outcomes don’t come to pass [1] [6]. In fact, by preparing for the worst, there’s a chance we actually decrease our suffering down the road [7]. In contrast, trying to “correct” negative thoughts can actually intensify them.

Of course, there’s a cultural component to positive thinking, and the relative benefits of negativity versus positivity vary depending on societal attitudes toward happiness in a given region. (For example, European Americans often find positive feelings to be more relevant to life satisfaction, while Asian Americans generally find negative feelings to be most relevant to assessments of overall happiness.) [8] [9]. It’s also important to note the effectiveness of positive thinking depends on individual factors like anxiety, coping mechanisms, and belief systems, so each person has to find what works for her or him [10].

But regardless of a given person’s traits or hometown, researchers suggest it might be better to acknowledge negative emotions instead of denying them — and then let them pass. An emerging style of psychotherapy, called Acceptance and Commitment Therapy (ACT), suggests we should accept that negative thoughts are guaranteed to come up. Instead of devoting energy to suppressing negativity, we should concentrate on identifying and committing to our values even amidst a swarm of negative thoughts.

Balance Positive — The Takeaway

We’re certainly not advocating that everyone become a sourpuss for life; just like negative thinking, positive thinking has its proven benefits, both physically and psychologically [11]. The trick, says Banschick, is finding the balance between being optimistic and being realistic. In other words: Stop and smell the roses, but first check for dog poop on the sidewalk beneath your feet.

Thanks to Greatist Expert Mark Banschick and professor and author Julie Norem for their contributions to this article.

Do you always look on the bright side, or have you embraced your inner pessimist? Share in the comments below, or tweet the author @LauraNewc.