The daffodils looked like they were dancing.
Throughout the poem, the speaker describes what he is seeing as he is daydreaming laying on his couch. He starts the poem by describing how he is floating like a cloud and suddenly sees "a host, of golden daffodils". He then goes on to describe the daffodils. He says the daffodils flutter and dance. He goes on to compare them to stars and sparkling waves. The purpose is to show how the daffodils provide a happy positive distraction that fills his heart with pleasure.