Every little gnat of irrelevancy may turn out to be what the poem is really about. Some poems come entire, bless them, dictated by the muse or ha-Shem or the tooth fairy. They may be important or trivial. Poems start from a phrase, an image, an idea, a rhythm insistent in the back of the brain. I once wrote a poem when I realized I had been hearing a line from a David Bryne song entirely wrong, and I liked it my way.
Some poems are a journey of discovery and exploration for the writer as well as the reader.
I find out where I am going when I finally arrive, which may take years. Poems hatch from memory, fantasy, the need to communicate with the living, the dead, the unborn. Poems come directly out of daily life, from the garden, the cats, the newspaper, the lives of friends, quarrels, a good or bad time in bed, from cooking, from writing itself, from disasters and nuisances, gifts and celebrations. The mind wraps itself around a poem. It is almost sensual, particularly if you work on a computer.