Certain table manners don’t really need an explanation. Chewing with your mouth closed saves others from catching a glimpse of your half-masticated entrée, and placing a napkin in your lap saves your pants from collecting rogue crumbs. But eating with your elbows on the table seems to be both convenient and comfortable. So why is it so frowned upon? Originally, it served as a tacit way to prove you were a non-threatening dinner guest.

“Table manners prevented us from leaving our space and starting a fight. It was important that people saw you as considerate or trying hard,” Margaret Visser, author of The Rituals of Dinner: The Origins, Evolution, Eccentricities, and Meaning of Table Manners, told Reader’s Digest. “People got scared when you started having bad manners. They realized the taboo was not functioning and you didn’t know what this person was going to do next.”

In other words, elbows on the table disrupted the border created by your utensils, which people could interpret as a general lack of restraint. It’s also definitely not a new rule; according to the Bible’s Book of Ecclesiasticus, you should be just as ashamed of “stretching your elbow at dinner” as “breaking an oath or a covenant” (though we can’t be sure that the verse isn’t referring to reaching for dishes across the table).

More recently, the no-elbows rule has become less about preventing brawls and more about avoiding other mealtime mishaps. “Not everyone is perfectly neat, so by keeping your elbows off the table, you are also making sure you do not put your elbow in a drip of salad dressing or soup or gravy,” Jodi R.R. Smith, owner and president of Mannersmith Etiquette Consulting, told MarthaStewart.com.

Keeping your elbows off the table also prevents you from exhibiting all sorts of bad posture that may have been viewed as a mark of an uncivilized upbringing. These days, a slight slouch at dinner probably won’t get you labeled as a Neanderthal, but leaning on your elbows might make it difficult for the people seated on either side of you to ever have a conversation.

That said, even some of the most faithful upholders of table etiquette have been known to break a rule or two. In a 1937 interview, Emily Post herself confessed to gracing the tabletop with her elbows from time to time. “It really makes no difference,” she said.

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