Feelings of relegation, homesickness, sadness of love, lack of talent, loyalty to the country, expression of scenery, lofty aspirations and so on.
In fact, although the times are changing, people's feelings have not changed much. If you carefully appreciate the words of the ancients, you may find something in common with him, just as the preface to Lanting Collection says, "The world is different, but it is so wonderful, and its purpose is the same."