From Mao Zedong's 1949 poem 《
七律·
和柳亚子先生》 (A Reply to Mr. Liu Yazi, in the seven-word regulated style). The couplet reads:
牢骚太盛防肠断,
风物长宜放眼量 — 'Too much grievance is harmful; one should always take the long view of worldly affairs.' Written to console his friend Liu Yazi, who was frustrated after moving to Beijing.