Too much happiness can make a person unhappy.
June Gruber, a psychology professor at Yale University has stated that – as with most of life’s pleasures – happiness is best experienced in moderation. “Research indicates that very high levels of positive feelings predict risk-taking behaviors, excess alcohol and drug consumption, binge eating, and may lead us to neglect threats.”
Psychologist Edward Diener adds that people who don’t experience much sadness in their lives don’t experience satisfaction with their jobs and don’t feel compelled to change careers or further their education.
The Washington Post writes:
Psychologists point out that emotions are adaptive: They make us change behavior to help us survive. Anger prepares us to fight; fear helps us flee. But what about sadness? Studies show that when we are sad, we think in a more systematic manner. Sad people are attentive to details and externally oriented, while happy people tend to make snap judgments that may reflect racial or sex stereotyping.
Source
Too much happiness can make you unhappy, studies show (Marta Zaraska, The Washington Post: April 2, 2012)