There are a number of non-negotiable, can’t-argue-with-’em skin-care commandments. You’ve got to stay hydrated (inside and out), wash off your makeup at night, and—this is a big one—keep your hands off of your face. The last is one you’ve undoubtedly learned as a child from your parents if those digits of yours touched your cheeks, nose, chin, or forehead (after, you know, being on germ-ridden public transportation or using the restroom).

Facialists and dermatologists alike are also always preaching that you should notpick your skin or touch breakouts, as it only makes things worse. While it’s certainly not an ideal skin-care habit to have, the true reasoning really became clear once I stumbled across a Reddit skin-care subthread about the issue.

Showcased in the thread was a super zoomed-in photo of a fingertip—and boy was it eye opening. “This is just a reminder to try not to touch your face too much,” the Redditor writes. “This is a magnified finger that shows the sweat/oils coming out of the pores.” You can view it below (sorry to do this to you).

It’s true though—the germs just keep piling up as you touch a zillion things throughout the day, and you do not want any of it on your skin. “One of the worst beauty habits you can have his touching your face during the day,” says Joshua Zeichner, MD, a board-certified dermatologist in New York City. “On a regular basis we are touching everything from door knobs to our cell phones. Dirt, oil, and bacteria buildup on our fingertips, which translates to skin problems if you’re touching your face.”

Those problems can be anything from acne breakouts to skin irritation or even infections, he says. If that—combined with what your fingertip truly looks like up close—doesn’t scare you from touching your face ever again, I don’t know what will.

To keep things clean, try a milky cleanser (which is good for sensitive skin). And here are facialist tips for washing your face.