If you've read Carol Dweck, you may recall the advice to praise what a kid has done (choices, actions), not who a kid is ("You are so smart.") Dan Willingham writes up a recent experiment, with 10 year old Dutch kids. (Hey Bo, your peeps!)
Kid fails. What happens if you praise "who he is" (i.e., the wrong kind of praise)?
And more specifically, what if he already has a poor self image?
....Adults are biased to do exactly the wrong thing--try to "buck up" kids with low-self esteem by offering person praise ("you're a great kid!") when these children will actually suffer more after a failure if they have received this praise.