Both rewards and punishments induce a behavior pattern whereby we try to impress and curry favor with the person who hands them out.  Whether we are looking to secure a reward or avoid a punishment is almost beside the point.  Either way, what we don’t have is the sort of relationship that is defined by genuine concern and that invites us to take the risk of being open and vulnerable – the sort of relationship that inspires people to do their best and can truly make a difference in their lives.

Alfie Kohn, from Punished by Rewards: The Trouble with Gold Stars, Incentive Plans, A’s, Praise and Other Bribes