One quote I've seen from Mao is "There is great chaos under heaven - the situation is excellent" (or "Everything in heaven is in utter chaos", "There is great disorder under the heavens", or other words to that effect). Google gives 11,600 hits for this quote and Mao. In Chinese it's "天下大乱，形势大好", according to Wikiquote. However, I haven't been able to find anything that gives the occasion he said this. Is there any evidence Mao actually said it?
According to Roderick MacFarquhar and Michael Schoenhals' book Mao's Last Revolution, Mao expressed his determination to create "great disorder under heaven" for the purpose of ultimately achieving,"great order under heaven." in a letter to his wife on July 8, 1966. There are no references to the exact quote in this book. But if achieving chaos was a political end to his means, and Mao was happy about the chaotic development during the proceedings of the Cultural revolution, the quotation is likely.