Why write poems? Why write poems?

is so
different from any other kind of writing.  There are no "rules," really, and you get
to form and shape your ideas any way you wish without worrying about the conventions of writing,
such as punctuation, capitalization, and complete sentences.  Poetry offers an opportunity to
express what you're feeling in a way no one else could, and frankly it allows you to say things
which need to be said (both awful and amazing) without everyone necessarily knowing all the
details.  You can tell how it feels or how it looks to you without telling all.  Conversely, you
can take the tiniest observation and give it a full and detailed expression in poetic form. 
There are certainly forms and conventions for poetry; however, at its core, poetry is a form of
expression which allows you to do whatever you want, however you want, as long as you're
expressing yourself.