What poems did ancient poets lament the lack of friends?

Li Bai: Until I raised my cup, I asked the bright moon to bring me my shadow and make the three of us. (Three people indicate the moon, the poet and the shadow. Think about it, Li Bai, drinking Alone with the Moon and till, raising my cup, I asked the bright moon drink together. People in the bright moon, suddenly turned into three people. In fact, they are still lonely. How helpless should they be? )

Du Fu: But there is no news from relatives or friends. I am old and ill, and I am alone with my boat. The poet's relatives and friends didn't hear a word, and the only thing they could rely on was the lonely boat drifting around ... alas, it's so sad. )

He Lanting: When you are a hundred years old, you can laugh for a few days, and you don't have many friends in your life. This sentence is easy to understand. A hundred years refers to a person's life. The poet lamented that life is only a few days, and there are not many confidants in life. )

Zhu Dunru: Things are as short as a spring dream, and human feelings are as thin as autumn clouds.