Po Bronson in New York Magazine on The Inverse Power of Praise:

By and large, the literature on praise shows that it can be effective—a positive, motivating force. In one study, University of Notre Dame researchers tested praise’s efficacy on a losing college hockey team. The experiment worked: The team got into the playoffs. But all praise is not equal—and, as Dweck demonstrated, the effects of praise can vary significantly depending on the praise given. To be effective, researchers have found, praise needs to be specific. (The hockey players were specifically complimented on the number of times they checked an opponent.)

Sincerity of praise is also crucial. Just as we can sniff out the true meaning of a backhanded compliment or a disingenuous apology, children, too, scrutinize praise for hidden agendas. Only young children—under the age of 7—take praise at face value: Older children are just as suspicious of it as adults.

Psychologist Wulf-Uwe Meyer, a pioneer in the field, conducted a series of studies where children watched other students receive praise. According to Meyer’s findings, by the age of 12, children believe that earning praise from a teacher is not a sign you did well—it’s actually a sign you lack ability and the teacher thinks you need extra encouragement. And teens, Meyer found, discounted praise to such an extent that they believed it’s a teacher’s criticism—not praise at all—that really conveys a positive belief in a student’s aptitude.

In the opinion of cognitive scientist Daniel T. Willingham, a teacher who praises a child may be unwittingly sending the message that the student reached the limit of his innate ability, while a teacher who criticizes a pupil conveys the message that he can improve his performance even further.

Bronson doesn’t make a case for having flaws pointed out, just that praise ought to be specific, not generic. To clarify my point: you should allow your non-critical weaknesses be visible to others, not necessarily draw attention to their existence in another.