In the mid-1980's, researchers at Cleveland State University made a startling discovery. 

They conducted an experiment by creating two fictitious job candidates: David and John. These candidates had identical resumes and letters of reference. The only difference was that John's letter included the sentence, "Sometimes, John can be difficult to get along with." They showed these resumes to a number of personnel directors. 

Which candidate did the personnel directors overwhelmingly prefer? The difficult-to-get-along-with John. 

These researchers concluded that criticism of John somehow made the praise of John more believable. Admitting John's wart actually helped sell John. 

As counter-intuitive as it seems, admitting flaws apparently provides greater credibility.  And this may be an important key in selling. 

-Author unknown