A purported connection between self-regulation and long-term positive outcomes, where the ability to forego immediate rewards is evidence of a discipline that serves in many other beneficial areas of life.
Named for the famous 1972 Stanford experiment led by psychologist Walter Mischel in which children were given the choice between one treat immediately or two treats if they waited. The children who waited, demonstrating 'delayed gratification', were shown to have indicators of successful behavior in other areas of life. Subsequent replications of this experiment have served to demonstrate that the associations were not as strong as originally thought, if not entirely explained by economic variables as opposed to willpower.
Our days are often a series of struggles between short-term satisfaction versus long-term discipline. The broader lesson is in appreciating the whole environment before making that quick decision — and we will often fail, only to be faced with an opportunity to practice our "Patience for the 2nd Marshmallow" again the next time.