From a Fortune article on happiness and success at work:
“The two most important predictors of success are, first, whether we believe our behavior matters, that is, whether we think we can make a real difference — and many people lose that belief in hard times, because so much is out of their control,” [Shawn] Achor [...]
There's more at josephzitt.com.
From the author of 19th Nervous Breakdown: Making Human Connections in the Landscape of Commerce
"Customers have told me that I approach bookselling like a ministry. Sometimes I find people exactly what they want; I hope that sometimes I find what they need. And helping the store make a profit is probably a good thing, too. But what I look for is the human contact, the communication, the chance to help people leave the store happier than they came in."