Erickson wants to look at what she calls "emotional labor" — or what nurses face in creating or suppressing their own feelings to make others feel OK. Nurses, for example, might have to hide their feeling of frustration and act happy with patients even when they're extremely overworked. This stress can contribute to burnout.

In the old days, says Dr Georgiades, running an airline meant making sure the same number of planes came down that went up. Now it's all about 'emotional labour.'

As I sat, five rows back in a Recurrent Training room at the Delta Airlines Stewardess Training Center in the early 1980s, listening to a pilot tell recruits to "smile like you really mean it," I remember noticing the young woman next to me jotting down the advice verbatim. I had already been talking for months to flight attendants from various airlines, interviews that are reflected in this book. So I had a sense of what feelings—anxiety, fear, ennui, resentment, as well as an eagerness to serve—might. underlie that smile.

It was that "pinch," or conflict, between such feelings and the pilot’s Call for authenticity that led me to write down in my own notebook, "emotional labor."