First of all, poetry is the most concentrated and direct catharsis of emotions.
This is because when a poet writes a poem, his emotional experience is the most abundant, vivid and distinctive. It's like the crystallization of salt deposited in seawater. The poet's warm emotion is a symbol of the temperature at this time. It evaporates the unnecessary transition and connection between poetry and poets, as well as all other thoughts and fantasies unrelated to poetry, so that poetry and poets are integrated, that is, neither affectation nor affectation (that is, evaporation of water vapor). This "condensed" crystallization is the birth of poetry. Therefore, the birth of poetry is the most concentrated (that is, condensed) and direct catharsis (that is, enthusiasm) of the poet's passion. Taking Li Bai's Shu Dao Nan as an example, we can easily see this point. Limited by space, I won't discuss it any more.
Secondly, as far as the poetic language itself is concerned, poetry must be refined.
If prose is compared to a trickle of emotions, and novels are compared to a long river of emotions, then poetry is a wave after wave in this trickle or emotion. It is a cross-section of prose or novel lyric. Therefore, it must be refined and not branched. In this sense, poetry is a refined expression of the poet's feelings at a time and a place.
Finally, poetry must contain the poet's strong feelings.
Poetry without emotion does not exist. On the other hand, emotions in poetry are all signifiable or interpretable (although there may be a certain gap with the creator's meaning). Why do we say, I like a poem, what have I learned from it, and so on? This shows that when appreciating a poem, the appreciator pursues the same emotional experience as the poet. Thereby expanding the personality (poet himself) to * * * (appreciator). This is the problem of "* * * singing" often mentioned in poetry appreciation. "* * *" The "song" here is the poet's passionate emotion.