(FORTUNE Magazine) – Hear it? That high-pitched, annoying, constant background noise? Maybe it's coming from the office next to yours, or from that little knot of people who have stopped to gossip in the hallway. Maybe it's even coming from--could it be?--you. One thing's for sure: It's getting louder and more persistent, and there's no getting away from it. If Walt Whitman were alive today, he'd have to rewrite his famous line from Leaves of Grass to read "I hear America whining."

If you can make out some of the words, they sound like this: The company doesn't appreciate me. The company won't help me plan my career. Nobody tells me what's going on around here. The boss is a knucklehead. My evaluation wasn't fair. My last raise was too long ago, and too small. Everything's changing too fast, and not for the better. Waaaaah.

A friendly word of advice to whiners (and you know who you are): Knock it off. Creating what Terry Ebert, a psychologist and managing director at the Ayers Group in New York City, calls "an atmosphere of chronic and pervasive self-pity"--all too common in recently downsized or restructured companies--is bad for your health, both mental and physical.

It can also cost you your job. Be warned. Roving bands of management consultants are out there telling your boss what your friends and colleagues are too kind (or too cowardly) to say to your face: If you can't find a way to overcome your disgruntlement, or at least turn it to some constructive use, you're poisoning the whole organization--or at least that part of it within earshot--and we really don't need that around here, do we? "And what a terrible waste it is, to be fired because of your attitude, rather than because of any lack of talent or ability," notes Mark Goulston, a psychiatrist and consultant in Santa Monica, California. "Because attitude problems, unlike a lack of talent, can be fixed."

Why does the richest nation in the world produce such prodigious volumes of bellyaching--even, or especially, among those who are lucky enough to have jobs? One answer, not as paradoxical as it sounds, is that we are the richest nation in the world, damn it. That is, our expectations of How Things Ought To Be were formed, consciously or not, during a run of astonishing luck that began in 1945. While we put a man on the moon and dared to dream of a Great Society, would-be competitors in London, Berlin, Dresden, and Nagasaki were still digging out from under. To the victor went the spoils--and perhaps inevitably, the complacency. Plenty of precedents for that: See, for instance, ancient Rome or the British raj. But this time, history's largess was overlaid onto a national character that already valued individual "rights" above almost all else, and still does. Psychologist Carol Tavris, in her landmark book, Anger: The Misunderstood Emotion, explains our tendency to whine: "The individualism of American life, to our glory and despair, creates anger and encourages its release. For when everything is possible, limitations are irksome. When the desires of the self come first, the needs of others are annoying. When we think we deserve it all, reaping only a portion can enrage."

Ah, "reaping only a portion," you may say, misstates the case. You don't want the whole pie, just a few more crumbs. Your co-workers got laid off, so you're working longer hours for the same pay as before; nobody ever says thanks. In fact, all your superiors do is keep raising the bar more, more, faster, faster. And then there's the rest of your life--the kids, the bills, the future...Well, welcome to the new world. You can't have the old one back. It doesn't exist anymore. The only question now is, how are you going to adapt?

Whiners don't. They self-destruct, usually with agonizing slowness. For one thing, the human body is not designed to tolerate long periods of futile rage. While you're watching your cholesterol, keep an eye on your mood too. In his book Anger Kills: Seventeen Strategies for Controlling the Hostility That Can Harm Your Heart, Duke University psychiatrist Redford Williams describes in chilling detail how being mad all the time can eventually shut you down altogether.

Robert Kerns, who teaches psychology and neurology at Yale, adds another reason to mellow out. His studies show that wallowing in negativity aggravates chronic physical pain (backache, headache). Other studies suggest that anger also suppresses the immune system, leaving you open to a wide variety of bodily ills, including cancer.

Those folks whom New York City behavioral scientist Deborah Bright calls "entitleists"--a polite word for whiners--often express their outrage in passive-aggressive ways, including being chronically late or absent, stealing from the company, backstabbing co-workers or bosses, or simply withdrawing--not taking risks, not suggesting solutions, not going the extra mile, in effect just waiting around to be fired. Need we point out that these are not great career-building strategies? Care to lay odds on who, in the next round of cost cutting, will have a bull's-eye sketched squarely on his or her forehead (and who will then be heard to cry, Waaaaah)?

Look. Everybody gets cranky now and then, and it's a rare duck who never misses the good old days. The point is, if you're habitually seeing the thunderhead behind every silver lining, you need to do yourself a favor and snap out of it. And you can. Contrary to what many people believe, anger is not so much a "natural" response as a conditioned one--and it is usually self-taught. The old folk wisdom that says you should count to ten before shooting your mouth off in a touchy situation is based on a bedrock truth: If you take a good, calm look at the circumstances, you may recognize that (1) you are reacting not to what is actually there, but to what you imagine (or fear) is there; and (2) the damage your tantrum can do may far outweigh the hazards of going with the flow. Stop. Look. Listen. Try to put yourself in somebody else's sneakers for a minute. It's entirely possible--indeed more than likely--that whoever you're mad at is even more stressed out than you are and means you, at bottom, no harm.

It could also be that if you examine your situation honestly, you'll find that complaining has become a way of trying to protect yourself from uncertainty. James Bailey, an organizational psychologist at Rutgers whose corporate clients are often in the throes of downsizing, observes that human beings have a terror of randomness, along with a deep-seated need to believe the world is fair. So, on some barely conscious level, bitching and moaning all through a big project is intended to accomplish one of two things: If you fail, you get to say, "See, I told you this wouldn't work." And if you succeed, you can say you made the thing fly in spite of all kinds of real or perceived obstacles--not enough people, a screwed-up computer system, or whatever. In your own eyes, you're a hero either way.

But the reality as others see it is, alas, a different story. Once you make a name for yourself as a big-league crybaby, you've put yourself in a no-win position. Either you've tarnished your own triumph with your constant kvetching or--worse yet--you've publicly predicted your own downfall. So next time you catch yourself griping, think about why you're really doing it. Consider whether the energy behind the jeremiad might not be put to some use that is less risky to you (and less boring to everybody else), such as trying to figure out how to fix some of the things that bug you.

A profound and nagging sense of loss and grievance toward your work, and by extension, your life, may mean you've lost touch with things that matter to you: bird watching, softball, Russian literature, old friends, the bluegrass band you used to play in--whatever floats your boat. Reach for the sense of perspective that comes from dwelling on something besides the office, even if it's just for an hour or two each week. And while you're at it, try to see yourself as a global citizen. The World Bank recently reported that about 1.3 billion people on the planet get by on less than $1 a day. Less than $1 a day. To at least 20% of the human race, you're virtually in the same league with Bill Gates. Now, what was that about your last raise? You didn't like it? We don't mean to be rude, but how about getting over yourself?

When they talk about banishing self-pity, many therapists sound a lot like your grandmother: Count your blessings, honey. It's good advice. Santa Monica shrink Goulston suggests you make a list of everything in your life that you feel grateful for, including everything that turned out better than you'd expected, and everyone who has ever helped you--whom you should then find a way to thank, even if it's 20 years late. "This sounds very simplistic," Goulston says, "but do it anyway." Why? "Because you'll find that you can't be grateful and bitter at the same time."

Or, as Abraham Lincoln put it over 100 years ago, most folks are about as happy as they make up their minds to be. Now is the moment to start making up your mind. You might want to do it before you really have something to complain about.