"The connection between confidence (whether earned or imagined) and performance has a great deal of scientific support. Numerous studies over the years have found that thinking you will succeed helps you succeed, in a variety of contexts. For this reason, deceiving yourself about your intelligence when taking a test or about your competence during a job interview can have tangible benefits. Whether you are above average or not, thinking you are can assist you in achieving above-average results."
—I love this book.
The Liar in Your Life, by Robert Feldman.