Almost every line of this poem describes a man by stacking one opposite on top of another: perfectly flawed, abnormally commonplace, a hard worker who hardly works. The effect is a portrait of someone who can't be pinned down. He seems lazy and unfinished, yet he is also restless, dreaming of being ordinary, of simply blending into a crowd.
The speaker keeps returning to one idea: to know him well is to know nothing at all. He is hidden even from those closest to him. His silence is loud, his stillness moves people, and his anger gives him a strange kind of joy. He "stabs the air with his words," lashing out at nothing in particular, which suggests frustration with no clear target.
The mood is wry but uneasy. The speaker sounds part amused, part puzzled, and perhaps a little sad. Judging by the repeated ending, the man stays a mystery, and the poem's circling structure leaves us stuck with him there.