The poem is a tiny scene with a joke at its center, and a sadness underneath it. A record is spinning and a room seems full of music, and then the speaker realizes something has gone wrong: the needle was never put down. The spinning is real, but the sound is not.
The first two lines build a picture of fullness. We imagine the room humming with song. Then the last line, set apart by the dash and the exclamation mark, pulls that away. The speaker's surprise feels sudden and a little embarrassed, like catching yourself in a small, silly mistake.
There's another way to read it, though. The "music" may exist only in the speaker's head, or in the idea of the moment. The room looks ready for music and feels like it should have it, but it's silent. That gap between what we expect and what's actually there gives the poem its mood: gently comic, a bit lonely, and quietly aware of how easily we can mistake motion for meaning.