Nature brings Wordsworth joy in "I Wandered Lonely as a Cloud" and is the gift that keeps on giving.
As the poem begins, Wordsworth, who loves to be out in nature, is wandering around feeling sad and alienated when he sees thousands of daffodils swaying in the breeze in front of a lake. They seem to be dancing. They appear alive and joyous to him, and his loneliness disappears as he watches them. It is if they are a happy crowd of people.
The daffodils give Wordsworth joy the moment he stumbles upon them, but that is not the end of the story. When he is lying "pensive," or thoughtful, indoors on his sofa, he thinks again of the dancing daffodils, and the memory brings him renewed joy.
Memory and nature are both important to Wordsworth. Nature is, for him, a gift he can keep on remembering and finding solace in, even when indoors.