Optimism helps us learn from failure and it stops the downward spiral of negative thinking. The optimist is always willing to try again with a different approach.
Here is some science to back me up: “Optimists emerge from difficult circumstances with less distress than do pessimists, optimists seem intent on facing problems head-on, taking active and constructive steps to solve their problems; pessimists are more likely to abandon their effort to attain their goals.”
M. Scheier, C. Carver, M. Bridges. “Optimism, Pessimism, and Psychological Well-Being.” Optimism & Pessimism: Implications for Theory, Research, and Practice. Ed. E. Chang. Washington, DC: American Psychological Association, 2001: 189-216
“A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty.” – Winston Churchill