What does Arlie Hochschild mean by “emotional labor”? How does the concept help us understand the specific demands of work in the service sector? How do Miliann Kang and Adia Harvey Wingfield see it operating across racial & class lines?

What does Arlie Hochschild mean by “emotional labor”? How does the concept help us understand the specific demands of work in the service sector? How do Miliann Kang and Adia Harvey Wingfield see it operating across racial & class lines?