Why did Zhu Yuanzhang hate the founding general Lan Yu so much in history?

The reason is that he is proud of himself.

In the twenty-four years of Hongwu, Lan Yuduo made many military exploits, and Zhu Yuanzhang treated him with great courtesy. Lan Yu became increasingly arrogant and arrogant, raising many village slaves and adopted sons, and took advantage of the situation to act tyrannically. Lan Yu once occupied Dongchang Mintian and was questioned by the censor. Lan Yu was furious and drove the censor away. When returning from the northern expedition to the south, he arrived at Xifeng Pass at night. The official guarding the pass failed to open the door in time to admit him, so Lan Yu sent troops to destroy the pass and broke in, which made Zhu Yuanzhang dissatisfied. After Lan Yu returned from the western expedition, he was named the crown prince. Fu Lanyu did not want to be subordinate to Song and Ying, and spoke arrogantly when serving the emperor's banquet. Military lieutenants and generals were promoted and retreated, and the power was vested in him alone. This made Zhu Yuanzhang, who was consolidating and strengthening centralization of power, more deeply Feeling uneasy, he was eventually arrested and imprisoned for treason. They were skinned and stripped, their homes were ransacked, and three clans were exterminated. They were also implicated. About 15,000 people were killed, from the Duke to the civil and military officials.