Love the vibe at Trader Joe’s? It’s all by design.

Anyone who makes regular trips to the grocery store knows: Don’t go on a Sunday, if there’s any way to avoid it. Stores are typically full of people trying to get their shopping done before the workweek and school week ahead. I made this rookie mistake a few months ago, venturing into my local Trader Joe’s on a Sunday evening. The small store was packed like its own delicious cans of sardines. A line — the end of which was demarcated by a red flag — wrapped around the outer aisles, so grabbing a loaf of bread required a diplomatic “Excuse me” and an awkward reach over someone’s cart.

It should have been super stressful. Instead, customers seemed to be coming up with inside jokes on the spot. Managers and employees, known as “crew members,” stopped by to chat. The vibe was less Hunger Games and more “in the trenches together.” It was like there was some magic spell keeping everyone in chipper moods. Trader Joe’s has its own, very particular vibe.

That’s no accident. Nearly 50 years after its sale to Aldi, Trader Joe’s is still as successful as ever. So successful that Stephen Dubner of the Freakonomics radio show even suggested that perhaps the U.S. should be run by the grocery chain. We spoke to industry experts, crew members, customers and even a self-proclaimed “superfan” to work out what the secret sauce is.

‘An escape from reality’

The parking lot was surprisingly full for a Tuesday morning when I recently visited a Trader Joe’s in the lower Hudson Valley of New York. There, I met Jason, a 52-year-old who manages a car collection. Jason, who did not want to share his last name for privacy reasons, is soft-spoken and visits Trader Joe’s about twice a week, when he isn’t traveling for work. During his trips to the store, “you feel like you’re going somewhere special — that’s an escape from reality,” he tells Yahoo. “How the products are displayed and everything else, it works for the playful part of the mind,” Jason added.

Trader Joe’s carries fewer products and displays a relatively small number of them, making it more manageable to navigate. It feels more like a farmers market (despite that it’s a national chain with more than 600 stores in the U.S.). Even its prepared foods somehow seem fresh and appealing, Lauren Beitelspacher, a professor of marketing at Babson College, tells Yahoo. “It’s all about the display and the consistency” in the quality of those products, she adds.

That sense of small-scale escapism may feel organic to customers, but it’s something the chain has worked hard to create. “Trader Joe’s does a lot to make the experience of shopping there feel special,” says Beitelspacher. “It’s affordable, so you feel like you’re getting a good deal, and they have products that you can’t get elsewhere.” Trader Joe’s is known for stocking some products seasonally and others for only a limited time.

That helps to make every trip feel like a treasure hunt. “It’s fun to shop there because they have seasonal options, so it feels like every time we go there, there are new things popping up,” Trader Joe’s superfan Elly Schommer tells Yahoo. The chain doesn’t have every ingredient that Schommer, a Phoenix home baker and mother to a teenage daughter, needs for baking (though the egg and butter prices are impossible to beat, she says), so she does shop at Fry’s Food Stores for those staples. “It’s fine, but it doesn’t feel like that novelty experience” you get at Trader Joe’s, she says. “It feels like an errand, whereas I would truly go to Trader Joe’s without needing to buy anything.”

The friendliness factor

Writer and content strategist Mark Gardiner literally wrote the book on Trader Joe’s and its brand strategy a little over a decade ago. He says the secret to Trader Joe’s success is the people.

Cliché? Perhaps. True? Well, it’s certainly a top factor that came up in every conversation I had about the store. “Trader Joe’s magic ingredient is that they hire a certain kind of person,” Gardiner tells Yahoo. “That person is extroverted and naturally chatty, and they want to interact and make friends with the customer,” he says. “That is the thing.” Gardiner, a chatty extrovert himself, went undercover (sort of) to test his theory. He applied to be a crew member at Trader Joe’s and landed the job.

Instead of learning how to operate a cash register at orientation as he expected, Gardiner’s training was mostly a series of role-playing activities that gave new-hires practice interacting with customers, showing them where the nonfat Greek yogurt is, or making conversation over the register. And when he and his cohort of about 50 were asked to introduce themselves to the group and their new boss, Gardiner thought he might have to be the first one to speak since “most people fear public speaking more than death,” he says. But he was wrong again. Almost everyone in the group raised their hands to speak, says Gardiner. “I thought, Oh my God, I have just seen the secret” to Trader Joe’s success, he says.

It works for Schommer. “It’s the schtick with the cashiers: They generally want to chat with you about your day, which I love, though I don’t know if it’s for everyone,” she says. When Schommer recently asked one cashier she’s gotten to know how his day was going, he answered: “Good! I’m at my second favorite place in the world,” beaten only by home, says Schommer. “I get the sense that every employee is happy to be doing their job.”

At least one employee (ahem, crew member) I spoke to at a Trader Joe’s said she is indeed happy to be doing her job. Sue, who preferred not to give her last name, started working at Trader Joe’s a year ago. She had never worked in retail before but heard great things about the company and its benefits. She says that working there has been “fabulous.” When asked what she thinks makes Trader Joe’s special for customers, she said: “We have a lot of unique products, and, number two, I think it’s just the environment; everybody’s friendly and super helpful.”

Sue adds: “We try to engage customers. It’s just a good place — the vibe is amazing.”

Quality over quantity

Unlike supermarket giants such as Kroger or Costco, you won’t find everything you need at Trader Joe’s. There are only a limited number of kitchen and pharmacy goods, and no massive stock of sodas, for example. That’s because — with a few notable exceptions, like San Pellegrino sparkling water and La Colombe cold brew cans — everything in Trader Joe’s is an in-house, or private label, product. Meaning, no Campbell’s vs. Amy’s soups, no Coca-Cola vs. Pepsi products. By and large, it’s all just Trader Joe’s own. “It’s something really special that this private label experience [creates],” says Beitelspacher. “It’s a risk, but they’ve built up the Trader Joe’s brand over time.”

Grocery stores make much better profit margins on their own private label goods, but they don’t have the same brand-name recognition as the products they resell. Grocery stores have massive overhead costs and slim profit margins of only 1% to 2%, typically. So most don’t want to incur the added expense of marketing their house brands. Without brand name recognition, customers are less likely to buy those products. By contrast, “Trader Joe’s built its [product] brand and tied it in with the brand of the store,” says Beitelspacher. “If people didn’t like their brand, then it wouldn’t be successful.”

But it was. Everyone Yahoo spoke to for this story praised the high-quality, relatively low-price, often organic produce; the Trader Joe’s prepared foods; the unique sweet treats and Takis knock-offs. And they praised how consistently good those products are. That’s key, says Beitelspacher. “You have to make a good thing that people like, and they have to like it repeatedly,” she says. Though Trader Joe’s does not publish financial data, both Gardiner and Beitelspacher suspect that their smaller stores, in-house brands and relatively low number of products help to keep costs low for the company (and customers) while padding its profits.

Another upside: The single-brand stock at Trader Joe’s prevents what psychologists call “choice paralysis.” In other words, when there are too many options, it becomes overwhelming and impossible to make a decision. Avoiding that is important for Melissa, a busy behavioral therapist and mother of two, who spoke to Yahoo at a Trader Joe’s. “It’s not overwhelming like a giant Wegmans,” she says. “You don’t have to wonder, ‘Oh, which brand should I buy?’ There’s just one.” That’s helpful because “I can get real indecisive,” she says.