Emotional intelligence--the ability to understand and manage emotions within yourself and others--often plays a greater role than "IQ" in determining success. And perhaps there is no place where this claim is truer than in business, where emotions play an outsized role in influencing who rises and who falls, who wins and who loses. In a surprisingly high percentage of business negotiations, transactions and interactions, it is emotions--especially negative or irrational ones, and not reason and rationality--that drive the agenda and outcomes.