Some people react quite negatively to positive reinforcement, either becoming openly defiant or withdrawing in a show of passive resistance. Are these acts of sheer perversity? Not at all. They are reactions to a very basic but rarely noticed fact: the most notable aspect of a positive judgment is not that it is positive but that it is a judgment. Older children and adults may hear praise as condescending, as a reminder of (or an attempt to bolster) the greater power of the person giving it. Suppose you are having a discussion about politics with some friends and one of them nods gravely after you say something and proclaims, "That is a very good point." Depending on a variety of factors, your reaction might well be intense annoyance rather than pleasure: "Who the hell is he to judge the value of my comment?"
-Alfie Kohn, Punished by Rewards