In his autobiography, Yeats wrote of "The Lake Isle of Innisfree":
I had still the ambition, formed in Sligo in my teens, of living in imitation of Thoreau on Innisfree . . . and when walking through Fleet Street [in London] very homesick I heard a little tinkle of water and saw a fountain in a shop-window which balanced a little ball upon its jet, and began to remember lake water. From the sudden remembrance came my poem Innisfree, my first lyric with anything in its rhythm of my own music.
In this poem, the speaker/Yeats longs to live in the simplicity of nature, with no extraneous distractions of city life or the superfluous habits, customs, and daily routines of an increasingly fast-paced, modern world. (Consider parallels with today's postmodern world; Yeats wrote this poem in the late 19th century.) Yeats indirectly invokes Thoreau in the first stanza when he says that he wishes to build a small cabin in the woods and live alone. Both authors recognized the allure of a simple life in nature, away from civilization. In "Where I Lived, And What I Lived For, from Thoreau's Walden, he writes:
I went to the woods because I wished to live deliberately, to front only the essential facts of life, and see if I could not learn what it had to teach, and not, when I came to die, discover that I had not lived.
Like Thoreau, the speaker of this poem wants to experience the "essential facts of life," life itself, and this is illustrated in the second stanza where the speaker looks to soak in the basic sights and sounds of nature.
Other than the appeal of getting away from the business of modern life (and into the simplicity of nature), the poem is appealing because it offers a mental (and potentially a physical) escape. The speaker is only dreaming of "getting away from it all." He repeats as if encouraging himself to actually do it, "I will arise and go now." Even if he never goes, he will at least have the mental escape. This is the saving grace; even if he can not get out of the city, he can imagine the escape as he can will himself to hear the lake water lapping even while standing on the pavement in the city:
I hear lake water lapping with low sounds by the shore;
While I stand on the roadway, or on the pavements grey,
I hear it in the deep heart's core.
There is another appeal/implication that one can never go back to the past place of nostalgia and youth, but through imagination and reflection, one can always have the mental escape and memory of another time and place.