The most overrated thing in business—and in life—is praise. Praise makes you feel terrific, but it’s not very illuminating because you almost always already know what you’re good at, don’t you? Criticism is the petri dish of improvement. Without awareness of what you could do better, you are unlikely to actually do it better, right? Why then do so many companies go to the trouble of asking customers to complete surveys, but then invalidate the responses by incentivizing the wrong behaviors?
http://www.convinceandconvert.com/customer-experience/faux-feedback-are-you-doing-customer-surveys-wrong/