Quan Cong
When Sun Quan wanted to send troops to conquer Zhuya (珠崖; present-day Hainan) and Yizhou (夷州; possibly present-day Taiwan), he asked Quan Cong for his opinion. Quan Cong replied: "Given the imperial might of our State, there is no territory that we can't conquer. However, these are distant and remote lands separated from the mainland by the sea. The local climate and geography may have been quite dangerous for mainlanders since ancient times. When soldiers and civilians live together, they are more likely to fall sick and contagious diseases will spread more easily. When that happens, our soldiers will never be able to come home. What gains would we have made then? I feel very unsettled by the thought of sending our troops, who are supposed to be guarding our borders, on such a risky mission with only a very small chance of success."