What was the speaker doing when he first saw the daffodils?

In this poem, the speaker is evasive about their exact actions. At the outset, the only verb that indicates any action on their part is "wandered." This could literally mean that the speaker was walking aimlessly at that moment, or it could refer more generally to their activities and attitudes over an unspecified period of time. The marked change in Line 3, "all at once I saw" is amplified in Line 11, when the speaker repeats the verb "saw." No other action is offered on the speaker's part. Rather, the flowers are said to be dancing or looking like they are dancing, and the waves dance as well. Again in Line 17, the poet says "I gazed—and gazed—but little thought...": the primary activity is looking, and the secondary is thinking but only a little.
Overall, the impression of passive observer is emphasized. Even when the speaker acknowledges a change in mood, they do so in the third person: "A poet could not be but gay...." The related shift is from "lonely" to feeling accompanied: "in such a jocund company."
https://www.poetryfoundation.org/poems/45521/i-wandered-lonely-as-a-cloud

He was "wandering lonely as a cloud." This is a metaphor for the poet's momentary loss of inspiration. The natural world was a deeply inspiring place for Wordsworth, as for many Romantic poets. He regarded it as a powerful, almost mystical force, with a life all of its own. It acted as a catalyst for artistic creation, fusing with the poet's imagination to generate enduring works of art. That's what Wordsworth means when he tells us that his wanderings were suddenly brought to an end by the sight of the golden host of daffodils, fluttering and dancing in the breeze. And whenever the poet finds himself experiencing a similar loss of inspiration in the future, all he has to do is cast his mind back to that glorious sight of nature, and his

heart with pleasure fills,
And dances with the daffodils.

In other words, his creative powers as a poet will have been awakened once more.
https://www.poetryfoundation.org/poems/45521/i-wandered-lonely-as-a-cloud