For a good long while, I let myself think that the slender platinum blonde behind the counter at Pret A Manger was in love with me. How else to explain her visible glow whenever I strolled into the shop for a sandwich or a latte? Then I realized she lit up for the next person in line, and the next. Radiance was her job.

Pret A Manger—a London-based chain that has spread over the past decade to the East Coast and Chicago—is at the cutting edge of what the Berkeley sociologist Arlie Hochschild calls "emotional labor." Emotional because the worker doesn't create or even necessarily sell a product or service so much as make the customer experience a positive feeling. Labor because, as Hochschild wrote in The Managed Heart (1983), the worker must "induce or suppress [his or her own] feeling" to achieve the desired effect in others. Creepy as it sounds, emotional labor is a growing presence in this economy, coming soon to a fast-food outlet near you.

The British journalist Paul Myerscough flagged Pret's reliance on emotional labor in a fascinating recent essay for the London Review of Books. (He called it "affective labor," a phrase borrowed from Marxist scholarship.) Pret workers, Myerscough noted, are required to master what the company calls the "Pret Behaviours," which in addition to the usual requirements—courtesy, efficiency, etc.—include "has presence," "creates a sense of fun," and "is happy to be themself" [sic]. (A list of the Pret Behaviours, posted on the company website before the London Review article appeared, has since been removed.)

Pret doesn't merely want its employees to lend their minds and bodies; it wants their souls, too. It will not employ anyone who is "here just for the money." Noting that one Pret worker in London got fired soon after he tried to start a union—the company maintained it was for making homophobic comments—Myerscough suggested the worker's true offense was being unhappy enough to want to start a union, since "Pret workers aren't supposed to be unhappy." The sin commenceth with the thought, not the deed.

Emotional labor is not itself new. Prostitutes have faked orgasms for millennia. With greater sincerity (one hopes), undertakers calm the grieving, nurses comfort the sick, and migrant nannies lavish on other people's children the love they aren't present to furnish back home. Flight attendants, in the pre-feminist era, calmed jittery flyers by being pretty, friendly, even a little bit flirtatious; this ended with deregulation in the early '80s as airlines stopped competing on service and started competing on price.