(FORTUNE Magazine) – By now, most of us have been schooled to believe we'll spend the rest of our careers jumping from job to job, working ever harder to prove our mettle to cranky bosses, and getting promoted much less often than our predecessors. We've been told over and over that this Darwinian odyssey is the new workplace reality, bleak though it may be. Yet the cheerful employees of our 100 Best companies face a far different, far more benign daily work life. These workers sing their employers' praises and--though it's very un-'90s--even declare pride in their corporate affiliation.

Why? What makes employees not just like but love these companies? We looked hard and found three recurring traits that seem to explain a lot. The great majority of our 100 Best have at least one, and many have all three. The good news is, they're within the reach of just about any employer.

First, many of our 100 Best are run by a powerful, visionary leader. Superstar CEOs like Bill Gates of Microsoft (No. 8), Andy Grove of Intel (No. 32), and Larry Bossidy of AlliedSignal (No. 96) are among the most demanding bosses in business, yet workers seem to feel inspired rather than oppressed by them; non-celebrities running many lesser-known companies have the same effect. Second, many of these companies offer a physical work environment that employees adore. Third, these companies often frame their work as part of a deep, rewarding purpose that employees find fulfilling. Here's a closer look at how a few companies on our list wow their workers.

INSPIRING LEADERSHIP. Exhibit A is Herb Kelleher, the Southwest Airlines CEO perched at the pinnacle of our 100 Best list. He spends his business life making sure his employees believe in him and in the operation he has muscled into the top tier of a savagely competitive industry. He smokes, he arm-wrestles, he drinks large quantities of Wild Turkey, he raps in music videos--and it is only slight hyperbole to say nearly all his employees worship the ground he walks on. But even he can't match the act of devotion displayed for Dave Duffield, the founder and CEO of PeopleSoft (No. 20), the software maker in Pleasanton, Calif. A few years ago employees formed a garage band and decided to call it The Raving Daves.

Remarkably, the well-worn story of Mary Kay Ash also retains its power to inspire. Those who know her well--and almost all who work for Mary Kay Inc. (No. 82) seem to think they do--describe her as a sort of corporate Everywoman: Pushed aside by her male superiors as a saleswoman in the 1950s, she quit her job and built a sales organization intended to empower other women.

Mary Kay's saga of how she grew her business and made a fortune is the chief inspiration for many of the 475,000 women who sell her products. "I was a secretary. I was not voted most likely to succeed in high school," says Lisa Madson, 37, who started selling for the company 11 years ago. "But she reaches so many people by talking about the potential that everyone has inside. And she's the living example."

Though Mary Kay herself is a millionaire many times over, the people who work for her marvel at her ability to remain accessible. Before she suffered a stroke in 1996, she used to invite employees to her home for tea several times a year. "I've sat on her bed and had cookies at her table," says Gloria Mayfield Banks, 41, an executive senior sales director based in Baltimore. "It takes away the mystery when someone totally opens herself up to you like that."

The effective leader inspires employees not just to work hard and succeed but also to become miniversions of the leader. That seems to be happening at Mary Kay. "People understand that for Mary Kay, it was all about fulfilling a mission that was bigger than just her," says Janice Bird, 42, who works at corporate headquarters in Dallas. "They've increased their own self-esteem by being around her, and they want to pass that on to others the same way she did."

KNOCKOUT FACILITIES. These may be the most persuasive way to tell employees they're valued. Top management at USAA (No. 39), the San Antonio-based insurance and financial services company, demonstrates the value of wooing employees with an impressive corporate compound. "Anywhere you go in town, if you tell someone you work for USAA, they're impressed," says Jeannette Leal, a service adviser in the life/annuity service and claims department. "You become a part of this place, and it becomes everything that you're about."

The amenities begin with an on-site child care center. The facility can handle 300 kids, and there's car-seat storage for families where the mom drops off and the dad picks up. In Tampa, where the company also has a large presence, they've even thought to add industrial-strength fencing around the kiddie playground in case marauding alligators show up in search of snacks. "My wife and I visited ten or 12 day-care facilities all over town," says Raul Nevarez, 30, a USAA security officer. "There was no competition at all."

If you don't want to drive to work, the company sponsors a van pool. If you ruin your hose, you can pick up a pair at the on-site store. There's a dry-cleaning service, a bank, and several ATMs. Even the cafeteria food is tasty enough that, several years ago, employees began demanding dinner to go. At Thanksgiving they purchased 5,620 pies and 188 turkeys to take home to their families.

Then there are the athletic facilities. The three gyms are indistinguishable from those at many upscale health clubs, and one is open all night long. Outside, employees compete in intramural leagues on basketball and tennis courts and softball and soccer fields. If you want to work on your backswing at lunch, there's a driving range too.

USAA employees clearly enjoy these breaks from their desks during the workweek, but they often return to the campus on the weekend with their families. "I enjoy bringing my kids here," says Donna Castillo, 34, a sales manager in consumer finance and auto service. "There are playgrounds where they can run around, and it's nice to take pictures of them here when the bluebonnets come out in the spring."

Amenities like these cost a company a lot, but they buy a lot too. "The facilities say that the company cares about us, that we're a valued asset," says security guard Nevarez. "People are dying to get in here. I have to go direct traffic when the parking lot at the employment center overflows. It makes me feel really good that I work for a company that is sought out like that, but it also means that I have to produce in order to earn the right to stay."

A SENSE OF PURPOSE. What sort of mission turns employees on? Well, it's not shareholder value, that's for sure. "I always try to make this very clear to analysts who cover our company," says Bill George, 55, CEO of Medtronic (No. 47), a medical-products company in Minneapolis. "Shareholder value is a hollow notion as the sole source of employee motivation. If you do business that way, you end up like ITT."

Most of those analysts love Medtronic anyway, largely because its employees turn out so many great new gizmos that a full 50% of revenues come from products introduced in the past 12 months. Shareholder value? The company's total return to shareholders has averaged about 34% annually over the past decade. But that isn't what gets workers out of bed and into a lab coat in the morning. Rather it's the notion of helping sick people get well. Instead of concentrating on shareholders or doctors, workers at Medtronic concentrate on the people who will have the company's products implanted inside them.

This is hardly a new approach for companies in the health and medical industries. Employees at Merck (No. 9), a perennial all-star in surveys of worker satisfaction, have long since memorized the mantra that the medicine is for patients, not profits. Medtronic finds novel ways to teach similar lessons, embodied in the company motto, "Restoring patients to full life." Its symbol is an image of a supine human rising toward upright wellness.

The resurrection imagery comes to life each December at the company's holiday party, where patients, their families, and their doctors are flown in to tell their survival stories. It sounds like the stuff of a made-for-TV tearjerker, but this is not PR gimmickry; journalists are generally not invited. Instead, it's the employees who are moved to tears year after year. "I remember going to my first holiday party, and someone asked me if I had brought my Kleenex," recalls Medtronic President Art Collins, 50, a strapping guy with a firm handshake who is generally not prone to crying fits. "I assumed I'd be fine, but then these parents got up with their daughter who was alive because of our product. Even the surgeons who see this stuff all the time were crying."

Improving human health, though in a much different way, was the deep purpose motivating John Mackey, 44, when he helped start Whole Foods Market (No. 34), a chain of natural-foods grocery stores. That clearly stated mission has helped him draw motivated employees who are more educated than the average grocery worker. Take Lisa Shaw, 30, a Wellesley College graduate who works in Brighton, Mass., for one of the company's Bread & Circus stores. "I remember going to a wedding after I graduated and seeing the looks on people's faces when I told them what I was doing," she recalls. "I just hang on to the fact that my job is good in some larger sense. If people buy the sprouts, they're eating healthier foods, the farmer is doing well, and it's good for the planet because they're grown organically."

Such high-minded talk makes it tempting to dismiss Whole Foods employees as a bunch of hippies running an overgrown cooperative. But Whole Foods is a public company whose margins are roughly 50% higher than the average grocery chain's; its total return to shareholders over the past five years has averaged about 23% annually. And the people who work there make explicit connections between the company's financial success and its larger goals. "We're going to pass a billion dollars in sales this year," says Linda Fontaine, 38, the national tax coordinator at corporate headquarters. "All that means is that we've just made that much more of a difference in the world."

Blissed-out employees working in the best of economic times are fairly easy to please, of course. A better test of worker resolve comes when a company slams up against a serious crunch. TDIndustries (No. 5), a specialty construction and service-repair business in Dallas, fell on hard times when building in that area practically stopped at the end of the 1980s. The company's bank had failed, and private investors wouldn't touch the place. So in 1989 CEO Jack Lowe took the problem to employees, who decided to terminate their overfunded pension plan. They could have put the $4 million thus liberated directly into their IRAs, but instead many of them elected to bet their retirement money on Lowe's bailout plan. All told, TDI employees put about $1.25 million back in the company in return for shares in an ESOP account.

A risky investment? Absolutely--but the value of those shares has more than doubled since then. Besides, it wasn't the money that people were worried about anyway. "Sure, we were fixing to lose a lot of our retirement funds if the company failed," says senior project manager Laura Price. "But the real fear was of having to go work for someone else."