...happy people make more money, take fewer sick days from work, get along better with their colleagues, spend more time volunteering, are more likely to help strangers, receive better supervisor evaluations on the job, are rated more highly by customers, and exhibit less work turnover than less happy individuals. These are bottom-line facts that tend to be welcomed by managers and executives."
Page 12, Positive Psychology Coaching by Robert Biswas-Diener and Ben Dean.