Hazel McKay's "Joy" is built on a simple trick: the speaker tells us what she isn't feeling before she tells us what she is. Happy, ecstatic, excited are all good feelings, and we might expect any of them to be the answer. Instead, she sets them aside one by one, as if none of them quite fits.
Then comes the last line, with "Joy" standing alone. The pause before it matters. After three short denials, the single word feels bigger and calmer than the ones she rejected. Happy and excited suggest something bubbly or loud, while joy, the poem implies, runs deeper and sits more quietly.
The mood is gentle and still, even a little surprised. The speaker seems to be searching for the right word and finally finding it. The poem's short lines and plain wording let that moment of recognition land clearly. It leaves you thinking about how often everyday words fall short of what we actually feel.