Bonuses don’t work. They do not lead to increased performance or better client satisfaction. What works is a job situation that includes autonomy (let me be part of decisions), mastery (let me improve) and purpose (let me define and understand purpose).
Do I work for free? No. Compensation has to take the money issue off the table. People don’t want to feel used, they want to feel fairly compensated. Above that, monetary incentives don’t work for any task that requires conceptual and creative thinking.
This has been my perspective for years. So, I was happy to see this attitude proven in scientific research (like in MIT and University of Chicago). Check out this video which illustrates a talk Dan Pink gave at a British version of TED.