Gratification is the pleasurable emotional reaction of happiness in response to a fulfillment of a desire or the fulfillment of a goal. A person may proudly say they are gratified upon achieving a hard won goal, and the term is usually used to refer to these cases. An alternate disparaging term instant gratification is used to label the satisfactions gained by more impulsive behaviors.
The skill of giving preference to long term goals over more immediate ones is known as deferred gratification or patience, and it is usually considered virtue. Critiques of the behaviors of others may highlight the lack of this skill. For example we might say that those who lack the skill are immature. But then, an excess of these skill can create problems as well; i.e. an individual become unable to take pleasure in life, seize opportunities, or remain flexible.
Gratification, like all emotions, is a motivator of behavior and thus plays a role in the entire range of human social systems.