Because Queen Xiao's words made him feel ashamed, thinking that he was repeating the same mistakes of the Sui Dynasty's extravagance. Li Shimin was a very accomplished emperor in history. As we all know, his father was Li Yuan, who was an official in the Sui Dynasty, and his mother also came from the royal family. It can be said that Li Shimin was born very prominent.
According to legend, when Li Shimin was 4 years old, a fortune teller came to his home and told Li Yuan that there was a noble son in the family, and he had the appearance of Jackie Chan. He was talking about Li Shimin. As soon as Li Yuan heard this, he told Li Shimin I took this name in the hope of benefiting the world and bringing peace to the people. Li Shimin was indeed very courageous and resourceful when he was a child. He was familiar with Confucian classics and was also very good at martial arts. He especially liked riding and shooting and had a very tolerant personality. When he was fifteen years old, he married Sun as his wife.
Two years later, when he was young, he went to war with his father on the battlefield. Seeing the corruption of the Sui Dynasty, Li Shimin gave his father an idea and asked Li Yuan to lead troops to resist. So they started in Jinyang He raised an army and followed his father to fight all the way, and finally established the Tang Dynasty in the first year of Wude. Later Li Shimin was named King of Qin. However, Li Yuan's character was too abrasive, and he had previously promised Li Shimin to make him the prince after the Tang Dynasty was established, but he went back on his word and made Li Jiancheng the prince, which led to a war between the two children.
Of course Li Shimin won in the end, but the Xuanwu Gate incident also caused many people to have prejudices against Li Shimin. But none of this can deny all the policies that benefited the people during his reign. Marrying Empress Xiao and incorporating her into the harem was just a drop in the ocean of all the things that happened during his reign. It also fully demonstrated that Li Shimin had a very rich life experience, so Any little thing can give future generations a lot of room for discussion.