Many people think that one of the important things English courses and English teachers do is teach people how to "analyze" poetry. I don't think that such an activity actually exists at all, and when people do engage in what they call "analyzing" poetry they do it only in English classes, and only to demonstrate that they've actually read the piece they're writing about. In other words, like essay writing generally, it's a skill you master in order to make sure you'll never have to do it again the rest of your life.
Analysis, according to the Merriam-Webster online dictionary, is "1 : separation of a whole into its component parts 2 a : the identification or separation of ingredients of a substance b : a statement of the constituents of a mixture." That's almost never what anybody's doing when they write an analysis of a poem -- and when it is, it turns out to be a list of components (this poem is an Italian sonnet, so it has iambic pentameter fourteen lines, of which the first eight pose a problem and the last six resolve it . . . and so on). Analyzing fiction is even harder to think about, because there's no agreement about what "the parts" might be. What we really do when we write essays in English class about works of literature would be better called "appreciation."
But in any case, I don't know of any English class (except this one) where those pieces of writing, whether we call them "analysis" or "appreciation," really serve any purpose other than to demonstrate that the writer has read and understood the piece of literature in question.
And it's not a kind of writing that gets done anywhere in the world except in English classes. Even English professors, writing articles for scholarly journals, don't write pieces which explain what's in a work. What they do when they write about one work, generally, is say that other people have missed something important about it.
So why do English classes so often ask people to write "analyses"?
Some of the reason, of course, is just habit. It's what we've
always done. And there are what could be called "spinoff
benefits" to the process: some people do learn to do a certain kind of
thinking about texts by writing literary essays, and there are, I'm
assured, people who learn about mechanical issues -- grammar, spelling,
and so forth -- by writing literary essays and having them red-inked by
a teacher. And there's an argument that reading "great books"
intensively makes you a more "cultured" person, and that asking people
to write analyses actually makes them attend to the books in a focused
way.
I think, though, there are better ways to learn those things, and to
become a "cultured" person -- and they involve (a) writing about issues
of real mutual concern for people who care about them (sometimes that's
a matter of what a text says and does, sometimes it's not) and (b)
becoming a person who reads "great books" for the rest of your life,
rather than someone who's encountered the eight or ten books you can
attend to in a course and then stops, considering the process over.
(This is what often happens when people spend time writing "literary
analyses."