Jeremy Holm splits his time between acting on shows like House of Cards and waiting tables. “I often have dreams where I come into work and everything seems to be fine … except that there’s no one else there,” explains the 30-year veteran of the service industry, who’s worked at the fast-paced Del Frisco’s steakhouse in Manhattan for more than 13 years. “The restaurant’s set up, but there are no other servers there, and suddenly there are a lot of guests coming in. And it’s just assumed that I’m waiting on the whole restaurant.”

If you hang around waiters long enough, you’ll notice a trend: many dream about waiting tables. Actually, they often have stressful nightmares involving wrong orders, unhappy customers, and small mistakes that snowball until they're "in the weeds" (completely overwhelmed). These dreams are known in the business as "waitmares." Uniquely grounded in the workplace, waitmares strike newbies and veterans alike.

mental_floss spoke to Robert Stickgold, director of the Center for Sleep and Cognition at Harvard Medical School, to find out what the brain is doing when it serves up a waitmare. (Though many people report work dreams—especially those in demanding roles—waiters seem to be unusually vocal about their stressful nocturnal experiences.)

Stickgold studies the nature of cognition during sleep, and the role of sleep in memory consolidation and emotional processing. His studies have appeared in Nature, Scientific American, and others, and have been featured on Radiolab and the NOVA episode “What Are Dreams?

Work dreams are "something that we see quite often,” Stickgold explains. “Not necessarily waiter dreams, but similar ones. They’re most commonly reported right at sleep onset. We get lots of reports of replay of the day.”

Holm says he often has minor waitmares as he’s drifting off. “I’ve forgotten something small, like a coffee or the extra horseradish that the guest requested," he says. "I’ll wake up and remember, ‘Oh, I really did forget the extra cocktail sauce for that guy.’”

That's the brain doing its job, according to Stickgold, who says sleep is crucial to improving performance after working at a task. “It’s the brain taking information that has had emotional salience, usually, about some sort of learning that we are constantly doing,” he says. “It could be as little as remembering to bring a person more coffee, because you have to create a memory to do that.”

By dreaming about forgetting to refill the customer's cup, the brain may be working toward helping you remember the next time you’re in the restaurant, he says.

That process—of learning while asleep—may be helpful for waiters currently working. But if you've ever waited tables, you know the dreams can persist years after you've stopped serving dishes. Artist Nicholas Forker hasn’t waited tables in 10 years—and just recently had a dream about being in the weeds: “I had a section of tables and I kept getting sat with new tables," he says. "No matter how many tables I took, I kept getting sat with more, and more, and more.”

Stickgold believes these dreams reflect what neuroscientists call "incomplete processing." The former waiters "still have some emotional ambivalence about those experiences—and there’s so many of them, there’s just this huge collection of memories," he says. "What the brain’s basically trying to do is help the individual … solve whatever feelings are left unresolved in the situation.”

So if you’re a waiter (or if you have a high-stress gig) and you keep dreaming about work, don’t worry—that’s just your brain helping you make sense of all the chaos. And little by little, with the help of dreams, you’re actually getting better at your job.