Why didn't Qi Huangong's grandson eat wine and meat for seven years in Spring and Autumn Annals?

Qi Huangong's grandson, Qi Qinggong, wanted to make great efforts to regain his hegemony, so he gave up wine and meat and pushed himself for seven years. Qi Huangong is the supreme ruler of power and prestige. At that time, Qi was rich and powerful, and everyone looked up to it. After the death of Qi Huangong, the son competed for the throne, and Qi declined for a period of time, so his strength could not keep up with the trip.

Later, his grandson acceded to the throne, known as Qi Qinggong in history. During his reign, envoys from other vassal states visited him. Coincidentally, the four ambassadors who came at that time were all a little disabled, which made Qi Qinggong feel a little funny. So after the meeting, he told his relatives about it. Some of them asked to see the four messengers again, and he agreed.

Before the four messengers arrived, he blocked all relatives who wanted to see the messengers behind the curtain, but when the messengers arrived, they gave a mocking laugh. A person's disability should not be a reason for others to laugh at him, what's more, how can it feel good for those messengers to hear these jokes with their own eyes? One of them vowed to wash away the shame.

Other vassal States were worried that there was no reason to attack Qi, but Qi Qinggong launched an attack on Lu. Qi Qinggong took the loyalty of Lu and defeated the Wei army. Sun Liang, who defends the country, intends to move reinforcements to the state of Jin, and the person who swore revenge came here with the army of the state of Jin. Qi was defeated by the armies of several countries. Suffering from failure, Qi Qinggong vowed to revive the hegemony of Qi, so he gave up drinking and meat for seven years, but in the end he failed to realize this oath.