There were some very cool studies many years back in which children were given opportunities to play with some toys. They really enjoyed playing with these toys -- it was fun for them. Then the researchers gave the children rewards for playing with the toys. Know what happened? The overjustifaction effect -- getting a reward for doing something that was intrinsically rewarding (it was fun to do all on its own) was now seen as totally different because they were getting rewarded for it. What happened was the kids no longer enjoyed playing with the toys. It became less about fun and more about "work". Still think that people do their best work if they get paid well for it?