Maybe you think no one notices the bald spot where you overzealously trimmed your beard this morning. Or cares that you used enough hair gel to seal the bricks in your fireplace. But someone does — and he’d like to tell you about it. Meet your long-suffering barber: The man who bears the brunt of your amateur-hour grooming aspirations. In fact, your barber has seen more grooming bloopers and styling gaffes in his years of practice than you will (hopefully) encounter in your lifetime. “As a third generation barber who has been cutting hair for over 20 years, I’ve pretty much seen everything,” Greg Zorian, owner of Gregory’s Barber Shop in Albany, NY, says. It only makes sense then, that if you want to know what not to do to your hair, he’s the man to ask. “The short answer is, if you’re not sure whether you should do something to your hair, you probably shouldn’t,” he adds. Here, seven cardinal sins of grooming ye shall not commit.