Thousands of workers now identify as their company’s “Chief Happiness Officer” or CHO. What does a CHO do every day? For Erika Conklin, CHO of a digital marketing startup, this month’s duties, included procuring beer and Jet Skis for a company retreat to Sarasota, Florida. She still deals with employee benefits and payroll. But she also works late signing contracts for company events or listening when co-workers need to vent about whatever makes them unhappy.

McDonald’s started the trend by “promoting” Ronald McDonald to chief happiness officer in 2003 as a joke. Then tech companies like Google joined the CHO bandwagon. The late Zappos Chief Executive Tony Hsieh was famously committed to a fun working environment. His book, Delivering Happiness, prompted other business leaders to give priority to workers’ emotional well-being.

But being responsible for others’ high spirits comes with a lot of pressure. There’s the expectation to always appear cheerful. And if morale sinks or the retention rate slips, the person with “happiness” in their title is likely to get some of the blame. CHOs often stress about their colleagues’ levels of happiness.

One CHO said, “Generally, I am very positive—my husband and my immediate family are the only ones who see the not-so-great side.” Another CHO polls her roughly 100 co-workers weekly so that she always knows the collective mood. “If there’s a dip, we ask, ‘Why?’” she says. “If it soars, we’re like, ‘What are we doing? How can we keep repeating this?’”