In the season three premiere of the brilliant FXX comedy “You’re the Worst,” Gretchen casually reveals something that repulses her boyfriend Jimmy — she doesn’t wash her legs. Gretchen doesn’t see the big deal, but Jimmy is righteously disgusted at the woman he shares a bed with, whose legs he often intertwines with his own clean ones.

This kicked off a fierce debate on Twitter, and Jezebel conducted a poll asking readers to indicate whether or not they believed in good manners. Only 53 percent of the 40,000 respondents said they washed their lower limbs — which make up quite a bit of acreage on the human body — when they shower.

This demands a national conversation. These people walk among us, and unlike Pigpen in “Peanuts,” there is no way to tell who they are — until it’s too late.

Failing to wash your shanks is an inexcusable offense for a few reasons.

The idea that water runoff properly cleans your steppers is ignorant at best. Sure, soapy water streaming down your leg on its way to the drain is better than nothing, but car owners will know that spraying water at a dirty object does very little to get the dirt off. Furthermore, the process of leg washing is a brief one, requiring just a few swipes of the loofah.

But why even wash something that doesn’t get dirty, these feral folks might ask. While it’s true that your calves don’t perspire as much as your armpits, there’s still sweat production going on, as anyone who ever strapped on shin guards can tell you. And the notion that your legs — the things that are always just a few inches above every dirty sidewalk you walk on and right up against every bus and BART seat you sit on — don’t get dirty is an outrageous one.

Lastly, a question of priorities. Showers are delightful. Every second spent in one is a slice of bliss. A while ago, on the heels of some deep shower thoughts, I did some math. I found that taking a 15-minute shower once a day for a year ends up costing about the same as a one-day pass to Disneyland, and I wholeheartedly believe that the shower is by far the preferable option. Which makes it that much more bizarre to me that folks would choose not to take the extra 15 seconds to scrub their walkers down. Why deny yourself both cleanliness and pleasure?

In “God Bless You Mr. Rosewater,” one of Kurt Vonnegut’s characters lectures a couple of babies on the ways of the world.

“Hello, babies. Welcome to Earth. It’s hot in the summer and cold in the winter. It’s round and wet and crowded,” says Eliot Rosewater. “At the outside, babies, you’ve got about a hundred years here. There’s only one rule that I know of, babies — God damn it, you’ve got to be kind.”

There are many ways one can be kind, some harder than others. But there are many things that one can do early and often and with little effort, and cleansing your dancing sticks is key among them.

“You’re the Worst” is centered around Jimmy and Gretchen’s deeply immoral lives, their tendency to drive in the midst of benders, their often brutal bluntness toward fellow humans, their inability to express — or perhaps recognize — their feelings for each other. But the leg washing has stuck as one of the few permanent problems Jimmy can find with Gretchen. There are cruder traits to her, things that many people would find profoundly disagreeable. But the leg-washing issue has stuck, and for good reason. Next time you’re in the shower, enjoying the dual privilege of hot and running water, squirt a little extra body wash out. Embrace the Full Body Clean.