You have to see this: The business case for happy employees

Centro has become very successful by crafting a unique corporate culture...

This video is superb: Shawn Riegsecker, CEO and founder of Centro, explains at a 2013 TechWeek event in Chicago, why he focused his company's culture on the happiness of its employees.

It's working: Centro has become a giant in the hot ad tech sector. With more than 500 staff and over $300m in revenues it is Chicago's fastest growing tech company. 

His staff attrition rate is an unbelievable 4% a year. He has no HR problems. Centro has now won "Best place to work" four years in a row -- no company has ever won the accolade twice in a row, in any city.

Please see:  Ad tech giant Centro aims to revive media industry