"I believe that I've got an almost built-in optimism. And I occupy myself more with problems of understanding and conviction than with problems of feelings or depression. On the contrary, I think that I am quite optimistic. It is Marxism, Chairman Mao, who has made us understand that people, especially communists, are optimists. Whenever I find myself in a difficult situation I strive to look for its positive aspect or for what potential for development may stillexist within that situation, because nothing is completely black, nor is anything completely red. Even if there were to be a big defeat, even though we have not had one yet, there would always be a positive aspect. The point is to draw out the lessons, and continue to do our work based on the positive aspect. You will always find someone to support you, to lend their ardent enthusiasm and assistance to the struggle, because communism unites people."
January 1, 1970
https://en.wikiquote.org/wiki/Abimael_Guzm%C3%A1n