Friends and family had a hard time understanding John Mitchell’s career move when he announced he was leaving his job as a commercial airline district manager to pump septic tanks. There was the inevitable snickering, and the wondering why someone would abandon a white-collar career path in favor of backbreaking and messy labor.But Mitchell, who wasn’t feeling fulfilled in the airline job, knew something the skeptics in his circle didn’t. Or, better put, he knew someone. Mitchell had watched as his friend, Dave Barnhart, owner of Evergreen Septic in Evergreen, Colo., build a successful pumping business. And he took note
