Warning: Daydreams Can Be Dangerous

Say what?

“You do not want your airplane pilot or your surgeon to mind wander,” Dr. Axelrod continues. “The same idea holds for every one of us.”

That logic seems fishy. Sure, if somebody is doing open-heart surgery, it’s probably not the best time for them to daydream about their upcoming vacation.

And you definitely shouldn’t daydream while driving—a 2013 study by the Erie Insurance Group found that daydreaming drivers are five times more likely to be involved in a deadly car crash than those distracted by their electronic devices.

Related: Why Do Sane, Non-Suicidal, Responsible Grown-Ups Still Text and Drive?

But if you’ve got a desk job, and you occasionally let your mind wander into a pleasant daydream, that’s not a big deal, right?

It can be if it’s making you depressed.

According to a 2010 study by Harvard psychologists, not only are people daydreaming during almost half of their days—47 percent of their awake hours—but those daydreams aren’t making them especially happy.

Study participants used an app, called Track Your Happiness, which asked them to share their current activity and mood. When they were just daydreaming, they reported feeling happy only 56% of the time.

Why do daydreams make people so miserable? Eli Somer, Ph.D., a clinical psychologist at Israel’s University of Haifa, says that mind-wandering can lead to unhappiness if the fantasies are too focused on unattainable things.

If you daydream about having athletic sex with a Victoria’s Secret model, or winning the lottery and quitting your job, or becoming the next J.J. Watt, you’re not doing your self-confidence any favors.

Too many of those daydreams and you won’t just be stuck in an emotional funk. Unrealistic daydreams become dangerous, Somer says, when people start to “prefer their inner fantasy worlds to engaging in real relationships and meeting their familial, vocational, or educational responsibilities.”

But not everybody agrees that an active fantasy life is detrimental. Jared Friedman, a researcher at the Brain, Mind & Consciousness Lab at Case Western Reserve University in Ohio, believes that “having a difficult-to-attain but still realistic vision for the future is tremendously important for motivation and psychological well being.”

In other words, stop daydreaming about the Victoria’s Secret model. But daydreaming about a super-attractive, smart and funny woman who you’ve admired from a distance but never found the courage to walk up and say hello—well, that may actually be a good thing. It keeps you motivated.

Related: How to Marry the Woman of Your Dreams, According to 12 Guys Who Did It

Sigmund Freud once called daydreams “imaginary wish fulfillments.” But perhaps a better way to think of daydreams is as goal inventories.

Winning the lottery is a wish—that’s not going to come true for you. (Or at least it’s so unlikely that we’ll take our chances with that statement.) Finding a better job that pays you more money—that’s a goal, and it could really happen. So use that as a gauge to filter the content of your daydreams.

Daydreams can also be hugely beneficial for creative thinking. “Moments of insight seem to creep up on us out of nowhere, and often during tasks which do not demand sustained and focus attention,” says Friedman.

Have you ever had a brilliant idea flash into your head while you were taking a shower, or doing dishes, or making the bed? That’s because our openness to creative insights “is best when we do repetitive, low-effort activities that allow mind wandering,” says Friedman.

Michael Kane, Ph.D., a professor of psychology at the University of North Carolina-Greensboro, suggests that mind-wandering can be useful even if it means doing a so-so job on the task you’ve actually set out to do.  

“That trade-off will often be worth it,” he says. “Either because the task we’re doing is relatively easy or unimportant, or because the progress we’re making on our future plans is great enough to be worth the cost to ongoing activities.”

You may forget to dry the dishes once you’ve washed them, but hey, you figured out how to ask your boss for a raise.

Related: The Smartest Way to Land a Massive Raise

Another reason to keep on daydreaming: When it’s done wisely, it can become an adaptive mental break, according Somer.

“During daydreaming, many people may rehearse a variety of challenging or threatening situations, to help them better tackle them in reality,” Somer says. “People may rehearse an anticipated meeting with their boss, review an argument with their partner, or plan a romantic gesture towards an attractive person.”

So yes, in the end, daydreaming really is dangerous. If you do it right, you’re mentally preparing for a better future. But do it wrong, and you’re setting yourself up for an emotionally debilitating depression.

The solution isn’t complicated. For a truly happy ending, focus on the fantasies that might actually come true.

Now, get back to daydreaming about that raise. And that hot girl you always see at Starbuck’s that you haven’t talked to yet.

Warning: Daydreams Can Be Dangerous