From Mercury retrograde to solar eclipses, it’s not uncommon for people to look to the cosmos in an attempt to explain unusual behavior. But historically, no astrological event has been blamed for abnormal events more often than a full moon. In fact, blaming the plenilune is such a common practice that it‘s got its own term: the Transylvania Effect, or the idea that the lunar cycle can influence human behavior. The theory has been propagated in more than one field: Medical practitioners have sworn the ER is crazier when the full moon emerges, law enforcement officers have claimed to make more arrests, and even hospitality workers have said guests are just flat-out rude. (Well, more so than usual.)

In the r/bartenders subReddit, bar professionals constantly lament the “horrors” of the full moon, with complaints ranging from attitudinal customers and stiffed tips to lengthy kitchen ticket times and even an uptick in physical fights. One user simply titled their post “F*CK FULL MOONS.” It’s not much better over on the r/ServerLife subreddit, where restaurant workers often discuss the “unhinged guests” they tend to and question how their fellow servers survived the night.

“Whenever there’s a large group of guests acting out of the ordinary, our front of house staff always ask each other, ‘Is it a full moon?’” said Kara Graves, senior partner and director of marketing for Charleston’s Uptown Hospitality Group. “[Guests will] ask for things like Tito’s and vodka instead of a Tito’s and soda, or ask to put something on a tab and not clarify the name on the tab.”

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So, why might the moon bring out the weirdest in people? Theories trace back to the first century A.D. when Roman naturalist Gaius Plinius Secundus (a.k.a. Pliny the Elder, just like the beer) posited that the full moon causes more dew to form in the air, leading to more moisture in the brain, and thus, madness. This idea persisted for so long that it forged the word lunatic, with its Latin root, luna, translating to “moon” and its suffix -atic meaning “of the kind of.” When the term rose to prominence in the Middle English period, it was used to describe an individual with alleged “moon-induced insanity.”

Theoretically, it’s not necessarily a reach to suggest that the full moon could have some impact on mood. If the moon is a factor in swaying Earth’s tides — which affect 352 quintillion gallons of water — might it be capable of influencing the water in humans’ brains and bodies? But in reality, there’s no concrete scientific evidence that suggests it’s possible. Emory University psychology professor Scott Lilienfeld told Astronomy.com that he’s “not aware of a single replicated finding in the literature that there’s a link between the full moon and odd behavior.”

The belief that the moon’s pull influences behavior was further debunked in a 2005 paper by Alina Iosif and Bruce Ballon in the Canadian Medical Association Journal titled “Bad Moon Rising: the persistent belief in lunar connections to madness.” In the paper, the two psychiatrists explain that rather than the moon solely controlling tides depending on its cycle, it’s actually the rock’s gravitational forces that do a lot of the work. They state that the only reason tides occur is because the moon’s gravitational pull acts on the 7,917.5-mile diameter of Earth, which reacts with comparable force. The human body clearly doesn’t have enough power to respond to the moon’s pull with comparable force, and therefore can’t be influenced in the same way.

As for why bar patrons may act a little stranger when the full moon comes out, Loren J. and Jean Chapman point to a psychological occurrence called illusory correlation. The term refers to the mind’s tendency to connect two unrelated events simply because they happen at the same time. When you’re aware of the astrological event and you notice something off-kilter, you’re more likely to take notice and attribute the goings-on to la lune because it fits in with your previous assumptions.

While it’s easy to look to the heavens when guests appear to be howling at the moon, they’d probably be acting the same way at most points in the moon’s cycle. But it’s no fun blaming the waxing gibbous, is it?