There is a unique sense of emotion which separates poetry from all other writing styles. While news is for briefing, fiction is for fantasy, and so on poetry leaves the reader with a feeling of familiarity. Poetry, as T.S Eliot once wrote is "leaving one still with the intolerable wrestle with words and meanings." What I believe Elliot meant by that was the intense feeling one can receive from reading a poem. This is commonly related to the readers personal relationship to their interpretation of the poem. Whether it be a stanza or the overall tone, if something in the poem brings a sense of familiarity to the reader than its purpose has been accomplished.
Poetry has a very therapeutic aspect from both the writers and the readers perspectives. Everyone is forced to face certain challenges, events, and celebrations throughout their lifetime, there is no escaping that. But by documenting and recording these thoughts, it is literally expressing yourself on paper. By releasing your most intimate feelings into an artistic outlet, you can be relived of containing so much emotion in your thoughts.
On the other hand, being on the other end of the paper has its benefits too. Philosopher Ludwig Wittgenstein stated "A poet's words can pierce us. And that is of course casually connected with the use that they have in our life. And it is also connected with the way in which, comfortably to this use, we let our thoughts roam up and down in the familiar surroundings of the words." The feeling of knowing that you are not alone is indescribable, especially if it is found in a piece of writing. Knowing that another human being has suffered or indulged the same way can give one a sense of comfort. .
Certain poems will "pierce" certain people, while other will not. Just as human beings are individuals, one poem can have a million different interpretations from a million people. What may make one person cry, can make another laugh, simply by the relation to ones self.