Can rewards for good behavior backfire? Talk amongst yourselves.

There's a good discussion going on in the comments of "How to use a star chart to encourage good behavior," interestingly enough, kicked off by an editorial tussle. We're now talking about how rewards can backfire; how kids' natural feelings of accomplishment and pride can get buried by the momentary excitement over a prize. I'd love to hear your thoughts on the matter. (I've turned off comments on this post so the discussion remains in one place.)