Most of the FBI agents I worked alongside would never utter the phrase emotional intelligence, much less attribute their success to it. While they considered themselves mentally tough, they preferred words like awareness and alertness to describe the skills they carefully honed over the years.
So what is mental toughness? It is being alert and aware of our emotions, thoughts, and behavior so we can manage them in ways that set us up for success.
Learning how to push through difficult situations while maintaining peak performance requires the ability to predict our responses so we can land on our feet — an impossible task unless we possess both self-awareness and self-management, two core components of emotional intelligence.

Via David Hain