Work is best when not driven by rewards and punishments. It is best driven by its own value - the difference it makes when the work is done, or the lost opportunity when not done.
The article ends with an observation that is very true.
So why are rewards and punishments employed so liberally?
"People like it because it is easy," Deci said. "It is easy to offer a reward, but it is not easy to help people find their own motivation."