Wordsworth is the granddaddy of all nature poets, and he’s in top form in "I wandered lonely as a Cloud." In her journal entry about the day in question, Wordsworth's sister Dorothy wrote about their surprise at finding so many daffodils in such a strange place, next to a lake and under some trees. "How’d those get there?" she wondered, even guessing that maybe the seeds floated across the lake. The event is one of the minor miracles that nature produces all the time, as anyone who has seen the documentary Planet Earth or the Disney movie Earth knows. Wordsworth’s nature is full of life and vitality. He appreciates its wildness and unpredictability, but he humanizes the landscape and fits it to his own mind.
Wordsworth espouses a philosophy similar to animism in this poem, in which the elements of nature are filled with spirits. The poem is deliberately pre-Christian.
The speaker would not have remembered the daffodils had they not been so out of the ordinary. After all, he had found nothing on his walk up to that point to get rid of his loneliness, despite being in one of the most beautiful places in England.