There was a time not so long ago that when you asked a colleague how he was doing he'd likely reply, "I'm good, thanks." He might not actually have been good at all, but he would have kept that to himself.

Now, in the age of the mortgage meltdown and mass layoffs, he'll probably offer the answer that's become the default comeback for white-collar guys who want to demonstrate they've got it all—the career on an upward curve, the remodeled townhouse, the hot wife, and the privately educated kids. He'll say, "I'm so tired."

"It's the first thing that comes out of someone's mouth when you ask them how they're doing," says Matthew Moss, 34, a creative director at a marketing agency in Portland, Oregon. "'Oh, I'm exhausted.' The first thing you think is 'Oh, this guy is tired, which means he's probably been working really hard.' Or 'They're full of shit.'"

Mostly, it's the second one. When you walk into a colleague's office and he's sitting there rubbing his eyes and stifling yawns, dropping a Venti latte cup into a wastebasket and hollering at his assistant to bring him another Red Bull, do you think, Wow, what an overachiever!? No. Because he's the guy who puts on the same show at meetings, trying to bleed extra credit from an average performance—Can you believe I pulled this off despite my obvious exhaustion?

"I think people use tiredness as a defense mechanism," says Paul (who asked that his last name not be used), 30, a vice president at an investment bank in Manhattan. "If you're staying till three in the morning you must be doing something very important, right?"

It doesn't actually matter what you're doing. No one believes you—much less cares. The three-day stubble, the slack jaw, the really . . . long . . . pauses . . . between words—to observers it's all white-noise whining. Mr. I'm So Tired thinks his cartoonish fatigue is demonstrating his dauntingly high station in life. It isn't.

"People use tiredness as a proxy for effort," says Steve Gravenkemper, an organizational psychologist at Plante & Moran, a consulting and accounting firm based in Detroit. "They say, 'Gee, I tried real hard even though I didn't get the result, and you can see that by my exhaustion.'"

Andy (not his real name), a 27-year-old analyst at a hedge fund in Manhattan, says the long hours that he and his colleagues work mean that there's low tolerance for status tiredness, because everyone is fatigued.

"It's like, 'Yeah, I popped two Lunes last night at 4 a.m.—and I was in at the office at six,'" he says. "It's really absurd."

Maybe it's that other symbols of social standing—the summer house, the SUV—are now so commonplace that they've lost their value. Or it could just be that to use tiredness as an emblem of status is to enter the realm of the intangible. No one knows what you did after you left the office, or whether you actually feel the way you're behaving. And the significance of the fatigued act is lost on them anyway. They're too tired to care.

Does bragging about how tired you are get under your skin too? Tell us your best "I'm so overworked" story in the comment section below.