Perfectionism begets self-doubt, and self-doubt begets an inability to operate at your full potential. The key, according to Arianna Huffington, is to ""evict the obnoxious roommate"" in your head. Arianna Huffington is the co-founder and former president/editor-in-chief of the Huffington Post Media Group, founder and CEO of Thrive Global, and author of 15 books, most recently the New York Times bestsellers Thrive and The Sleep Revolution.