Whereas positive mood seems to promote creativity, flexibility, cooperation and reliance on mental shortcuts, negative moods trigger more attentive, careful thinking, paying greater attention to the external world.
Scientist, Skeptic, Author
I am, by nature, an optimist. ... My optimism, however, has not always served me well. Twice I have been hit by cars [while cycling] that were entirely the result of my blissful attitude that the street corners I had successfully negotiated hundreds of times before would not suddenly materialize an automobile in my path. ...feelings — both positive and negative — too often trump reason. In the end, reality must take precedence over fantasy, regardless of how it makes us feel.