Even Mother Theresa, as wonderfully giving as she was, operated out of self-interest. It's fair to assume that doing good works made her feel good and that she believed those works put her on good terms with the Lord. Dr. Gerald Kushel, author and professor emeritus, has stated in his book Reaching the Peak Performance Zone , there are several variables involved in motivation. Motivational Intensity Intensity has to do with how strongly the person wants the reward. A person can be highly motivated, mildly motivated or only slightly motivated.
Motivation tends to last longer when it is reinforced intermittently rather than consistently.
Somehow, intermittent rewards are stronger. Psychologists have believed this for years. We tend to take for granted and not appreciate the thing that has become routine. There is a certain excitement factor in something we cannot take for granted or assume. Psychologists have taught us that the intensity and duration of a given motivator are enhanced if the reward is immediately given following the act or behavior.