As far as ideology is concerned, Emperor Yang Di left many stories about envy of talents and talents, which is undoubtedly a lesson worth remembering. On the surface, Su Yang, who made great contributions to this dynasty, was well paid and trusted, but deep down, he was very scared. At the end of his life, he sent someone to be caring and attentive, and sent the royal medicine to the Yang family. It seems that he is very worried. Because he is worried that Su Yang will not die soon, he secretly asks the doctor about his illness. Su Yang was well aware of the emperor's attitude towards him, so he didn't even take medicine after knowing that he was very ill. After Su Yang died, the funeral was grand, that's all. Xue Daoheng, a senior official, is famous for his literature, but he was sentenced to death because he wrote an article in memory of Emperor Wendi of Sui Dynasty and delivered a speech in memory of Gao Jiong, a famous minister. Yang Di once said to Yu Shinan, "I hate being remonstrated by others, especially those who are already in high positions but want to become famous by remonstrating. Even if a person is humble, I will tolerate it a little, but I will never give him a good future because of my suggestion. " In the 12th year of Great Cause (6 16), the situation has been chaotic, and Emperor Yang Di still hates people who tell the truth and is unwilling to listen to the report of the real situation. No one who opposes his going to Jiangdu at this time will come to a good end. Cai Zhao was detained and Injong was killed. Cui was full of thieves, and even brutally cut off his chin and beheaded.

Since then, fewer and fewer people have dared to give their opinions. Therefore, during the reign of Yang Di, a major event happened in which Yang Xuangan, the son of Su Yang, opposed the Sui Dynasty. Many participants were princelings of the Sui Dynasty. This is enough to show that Emperor Yang Di had a big problem in policy and politics, which caused a serious division of the upper class of the ruling group. From the bottom of society to the top of society, people are deeply dissatisfied with today's emperor and full of resentment. The national situation is about to collapse completely, and the first responsible person can only be the emperor Yang Di Yang Guang. What he did directly caused the Sui Dynasty to turn from prosperity to decline, which seriously intensified social contradictions, including class contradictions, and exceeded the tolerance limit of all aspects of society. Li Shimin learned a lesson from the demise of the Sui Dynasty. Although his arrogance inevitably increased, he did not stick to the style of Zhenguan's early years for a long time. After all, he is generally relaxed and has not caused serious social problems. Although Li Shimin was impatient with remonstrance, he once said in the harem, "I can't wait to kill the old man Wei Zhi!" But on the whole, I can still be humble enough to teach, try my best to hide my words, and at least basically tolerate the advice of my liegeman.