plumber

Since April, Chambliss has worked the night shift overseeing a team of 200 welders, plumbers and electricians at a local data-center construction site.

“He’s almost building a cult,” said Aaron Cook, a 28-year-old plumber who was in the audience in Las Vegas.

"In any customer service job, you want to bring a smile to your client's face, whether you're a chef, or a plumber, or just somebody working at a shop."

But most jobs aren’t focused on a single, routine task—think finance manager, or plumber.

The American middle class encompasses a broad cross section of workers that includes white-collar office employees, nurses and plumbers, although there is no universally accepted definition.