L'ottimismo conviene

If you are an optimist, you have a better chance of making a self-fulfilling prophecy. If you say this is a wonderful world and we can make it better, then there is a chance that people will listen to you and do what you say.

Fonte

Arthur C. Clarke, 1982, citato in Arthur C. Clarke, The authorized biography, Neil McAleer, ISBN 0809237202, p. 294