I wrote a staggeringly bad poem when I was 19 after a girlfriend dumped me. I seem to remember comparing her to a tarantula. It was all very E. J. Thribb of me.
I love to compare different time frames. Poetry can evoke the time of the subject. By a very careful choice of words you can evoke an era, completely throw the poem into a different time scale.
Comparing and contrasting is a valuable human skill - and not just during high school English exams. Our ability to rank-order things is invaluable in making choices and setting priorities.
Poems seem to have a life of their own. They tell you when enough is enough.