Sometimes being simple is artful. By keeping the poem’s structure and diction simple, Yeats was able to create for the reader the kind of simplicity he is describing. The poem is about finding a slower life. It is a stop and smell the roses poem. Its slow, meandering style reinforces its message. Take your time to enjoy life, and your life will be richer for it.
The speaker describes a simple cabin made of clay and branches in the first stanza. In the second stanza, the focus is on peace.
And I shall have some peace there, for peace comes dropping slow, Dropping from the veils of the morning to where the cricket sings;
The abab rhyme scheme of the poem seems to lap like the water along the island with a peaceful heart-beat like rhythm.
Peace and slow are emphasized as interrelated. When we stop to focus on the smaller things, we find ourselves at peace. We can leverage this peace to return to our hectic lives a little looser, and with a little more perspective.
Sometimes even thinking about a peaceful place like the little cabin on the island is enough to make a person feel better, and the artfulness of the poem partly comes from the fact that it does seem to so effortlessly transport the reader to the place being described, or at least the state of mind.