One point I've made a few times is that people tend to do what you give them an incentive to do, but the incentive isn't always what you think it is.
For example, if you give customer service reps a bonus if they score better on customer surveys, you might think you've given them an incentive to improve customer service. Not so: you've given them an incentive to improve survey scores, and if it's easier to manipulate the survey than actually provide better service, then manipulate the survey they will.
This effect becomes stronger the greater the penalty for underperformance, and can lead to some really perverse results.
Along those lines, here's an article claiming that some General Motors dealerships will refuse to serve customers who turned in less-than-perfect customer surveys. The incentive system (the author claims) is so punitive that it's cheaper for a dealer to "fire" a customer than risk anything less than perfection on the survey.
Somehow, I don't think that's the effect GM intended.