On September 13, 2015, you shouldn't lose any energy into negative thoughts, because on that date is the Positive Thinking Day. It was introduced in 2003 by an American entrepreneur to celebrate the benefits of positive thinking. It's best to start with a good thought ("Today is a good day!") into Positive Thinking Day.
Positive thinking is a concept that is known from personality or motivational seminars and advice literature. The goal of positive thinking is to ensure, that through constant positive influence a long-term constructive and optimistic attitude will be reached and consequently a higher satisfaction and quality of life will be achieved.
Optimists have been shown to live healthier lifestyles which may influence disease. For example, optimists smoke less, are more physically active, consume more fruit, vegetables and whole-grain bread, and consume more moderate amounts of alcohol. A meta-analysis has confirmed the assumption that optimism is related to psychological well-being.