Emotional Stability is the ability to discriminate ones own and others emotions and to be able to use ones emotions to guide our thought life, without our emotions ruling our thought life.
The appropriate use of ones emotions at the right time and in the right place is often quoted to be our emotional intelligence, which it is while at the same time affords to our emotional stability. Being in control of our emotions in pressurized situations is like a Fire Fighter calmly walking into a building where the occupants are running out.
The ability to address areas in our lives where our emotions tend to run our thought life rather than our thought life using our emotions to facilitate experiencing life in a dimension that allows one to enjoy more of whatever life throws at us rather than feeling like we are constantly attempting to dig ourselves out of trouble.
Emotional stability is living in peace.