It’s come to this: Would you even blink an eye if you saw a guy in a baseball cap at a nice restaurant? What if he were chewing gum? And ignoring the people he was with so he could keep glancing at his BlackBerry? And clutching a pack of cigarettes for his imminent smoke break? And answering his (loudly vibrating) cell while sitting right there at the table, saying something along the lines of “Yeah, we’re at dinner right now. I dunno, shouldn’t be much longer. . . . You’re with who? Her?! That skank? Dude, I can’t believe you’re hitting that! . . .”

Not only would none of this be shocking; it’d be depressingly normal. Because nothing—not self-restraint, or peer pressure, or cultural expectations—prevents guys these days from exulting in their own self-entitled disregard for other people’s comfort. It’s a way of broadcasting their brazen independence, their get-out-of-the-way manliness. Because, you know, they’re rebels.

“That kind of behavior comes out of the self-absorbed ‘me’-ism of childhood,” says Peter Post, director of the Emily Post Institute and great-grandson of its legendary namesake. “Early on, boys discover that rebelliousness and rudeness are impressive to their two or three best friends.” But as they grow up, some guys fail to look beyond their inner circle when gauging how their behavior might be perceived. Compounding matters is the fact that pop culture increasingly defines the masculine archetype not as the strong, silent type of the past (John Wayne, Clint Eastwood) but as the restless, rude punk with a marked lack of impulse control (Eminem).

“There’s this phrase, ‘defining deviancy downward,’” says Randy Blazak, an assistant professor of sociology and criminology at Portland State University, in Oregon. “We’re so bombarded with rule-breaking that we don’t know what’s appropriate anymore. This is about guys who want to reject the new masculinity, which they see as constrained and feminized, so they take on the boorish nature of the gangsta rapper or the prankster. ‘A man can do what he wants’—that’s how they define masculinity.”

Only problem is, guys who’ve convinced themselves that acting boorish is manly and having manners is gay are in reality doing something that’s actually rather homoerotic, in an anthropological sort of way: They’re unconsciously showing off for other guys. Because it sure as hell isn’t the opposite sex that gets off on hearing explicit talk about doing skanks and hos.

Which isn’t to say all traditional rules of etiquette—like saying, “Yes, ma’am” and “Yes, sir”—are worth bringing back. “But you need to know the rules, so you know which ones to break,” says Lauren Solomon, a New York etiquette expert and former vice president of professional-image development at Chase Manhattan Bank. “In real life, it matters the moment you don’t get the date, the moment you don’t get the job. People won’t tell you they think you’re juvenile or they think your mother did a bad job raising you,” she says, laughing ruefully. “But that’s ultimately what people base their decisions on.”