Toni Rodriguez in Scientific American:
A client sits before me, seeking help untangling his relationship problems. As a psychotherapist, I strive to be warm, nonjudgmental and encouraging. I am a bit unsettled, then, when in the midst of describing his painful experiences, he says, “I'm sorry for being so negative.” A crucial goal of therapy is to learn to acknowledge and express a full range of emotions, and here was a client apologizing for doing just that. In my psychotherapy practice, many of my clients struggle with highly distressing emotions, such as extreme anger, or with suicidal thoughts. In recent years I have noticed an increase in the number of people who also feel guilty or ashamed about what they perceive to be negativity. Such reactions undoubtedly stem from our culture's overriding bias toward positive thinking. Although positive emotions are worth cultivating, problems arise when people start believing they must be upbeat all the time. In fact, anger and sadness are an important part of life, and new research shows that experiencing and accepting such emotions are vital to our mental health. Attempting to suppress thoughts can backfire and even diminish our sense of contentment. “Acknowledging the complexity of life may be an especially fruitful path to psychological well-being,” says psychologist Jonathan M. Adler of the Franklin W. Olin College of Engineering.
Positive thoughts and emotions can, of course, benefit mental health. Hedonic theories define well-being as the presence of positive emotion, the relative absence of negative emotion and a sense of life satisfaction. Taken to an extreme, however, that definition is not congruent with the messiness of real life. In addition, people's outlook can become so rosy that they ignore dangers or become complacent [see “Can Positive Thinking Be Negative?” by Scott O. Lilienfeld and Hal Arkowitz; Scientific American Mind, May/June 2011]. Eudaemonic approaches, on the other hand, emphasize a sense of meaning, personal growth and understanding of the self—goals that require confronting life's adversities. Unpleasant feelings are just as crucial as the enjoyable ones in helping you make sense of life's ups and downs. “Remember, one of the primary reasons we have emotions in the first place is to help us evaluate our experiences,” Adler says.
More here.