Every business has sycophants, creeping around the corners, sucking up to the boss and reinventing the truth. Hire an advisor and his job likely becomes to advice you to do what you wanted to do in the first place. Advisors who voice dissent too often are soon out of a job. Most people dont keep "no men" around.
So whats wrong with surrounding yourself with yes men? Nothing, until the disaster that could have been foreseen drops into your lap and your board of directors is asking you to resign. Wall street is littered with the remains of CEO's who let their yes men convince them that their companies could manage the risk of derivatives. When the CEO's figured out the risk couldn't be managed, it was too late for them and their companies.
Reference. Warren Buffett. Management secrets.