(FORTUNE Magazine) – Over the last quarter century, various jobs have required me to cash welfare checks in Connecticut, clean dishes in Massachusetts, type obituaries in Vermont, buy tattoo designs in Hong Kong, and piss off Eurocrats in Belgium. But you never forget your first job--in my case, as counter help at the Dunkin' Donuts in Cos Cob, Conn., the town where my parents have lived for all but two of the past 47 years. So when FORTUNE asked if I would be willing to return for a week, I was intrigued enough to say yes. Was that a good idea?

That was the question I pondered at 6:30 the other morning as I put the 178th cup of coffee into the clutches of a caffeine-deprived customer. And the answer?

Well, you can go back behind the counter, but it's a different world. For a start, the Cos Cob store has changed hands twice since I worked there, and in 1990 Allied Domecq bought the then 40-year-old chain. There are more than 5,000 Dunkin' Donuts shops now, compared with 1,000 in my time. There are bagels and muffins and even hot sandwiches. The uniforms, thank heavens, are much superior to the boob-busting pink concoctions that I wore in 1977. Sadly, however, since a renovation in the late 1980s, gone are the stools and counters where a group of neighborhood philosophers used to solve the problems of the world every afternoon. "This place lost a lot of heart when they took out the counter," says Geoff Tatton, a regular then and now. He's right.

The biggest shift, though, is that in communities like Cos Cob--an affluent little place about 35 miles north of New York City that is part of the more famous, more pretentious, more fashionable, and altogether more precious Greenwich--the idea of the first job is changing. Dennis Tournas, who bought the franchise in 1983, prefers not to hire high school students anymore. Unlike in my day, when we teenagers were all paragons of dependability, kids these days hog the phone and cancel shifts at the last minute. But then, they aren't exactly begging to bag doughnuts, anyway. When the manager of the store, Jose Illescas, shows me a sheaf of applications, none are from local teenagers. And it's not just Cos Cob. The Bureau of Labor Statistics says that the labor force participation rate for young workers is at its lowest since 1972. The rest are presumably either interning at the World Bank to impress Ivy League admissions officers or simply hitting up mom and dad for cash.

So who's making the coffee? Immigrants. Every single worker at the Cos Cob Dunkin' Donuts, from the owners, who were born in Greece, to the manager (Guatemala), to the most senior baker (Brazil) and the longest-serving counter help (Taiwan), is an immigrant. These are not great jobs. Pay starts at $6.85 an hour, and there are no benefits to speak of. Some hope to work hard for a few years and return home with enough savings to jump-start their children's prospects. Others are struggling--with the language, with the society, with their fatigue. But it's not impossible that this can be the start of something better.

Take Jose Illescas. His first job at Dunkin' Donuts in 1976 was as a night cleaner, scrubbing the bathrooms and kitchen equipment. He now manages this and three other shops; he also owns a landscaping business and a home in Old Greenwich. Or Laura Lopera, a philosophy student from Medellin, Colombia, who has been in the country for six months. It's hard to imagine that she's going to be stuck behind the counter forever. Okay, her English is limited and dominated by doughnuts. But she's reading Dostoyevsky to build her vocabulary, loves Rimbaud, Plato, and Ambrose Bierce, and is stunned that I haven't read Kafka.

Some things don't change. Doughnuts and coffee are still the core items of the Cos Cob store, which grosses about $1 million a year. People are still pathetically grateful for their coffee and passionate about how it's made. They'll ask for something like "coffee with just a little milk and 3 1/2 sugars." And they'll watch to make sure your hand doesn't shake in a quarter of a teaspoon more sugar or a squirt too much milk. Early-morning coffee jokes are still unappreciated. Blue-collar men--particularly tree surgeons, for some odd reason--are still the best tippers. The coffee is still excellent. And Cos Cob's biggest cat--of the two-legged variety--is still on the prowl. She comes in, sees me behind the counter, and boggles. "Cait, you're working here?"

"Yes. What can I get you?"

No doubt the news of my precipitous career collapse will be on the grapevine in a matter of minutes.

Happily, Cos Cob still has a fairly robust tolerance for the eccentric. Late one afternoon a battered station wagon rolls in, appliqued with wings and a large shamrock. A big shambling wreck of a man enters, orders three sugared crullers, and leaves without incident. "He was okay today," notes Lopera, "but he's weird. Sometimes he comes in naked."

In my first Dunkin' Donuts tour, I learned a lot about Cos Cob and quite a bit about how to deal with people. I learned that in the workplace, not wanting to do something--say, frosting chocolate doughnuts--just doesn't matter. You have to do it, so there's no use whining. I learned how much smoother the day goes when people act with civility; a shift filled with pleases and thank-yous is better than one lacking in such grace notes.

The second time around, all this is still true. But it also struck me more than ever just how wearying it is to schlep doughnuts and coffee for hours at a stretch, how hard many people work for little reward, and how urgent the American dream still is.

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