In this poem, which single effect has the poet created by unifying literary elements?

Richard Cory
by Edwin Arlington Robinson

Whenever Richard Cory went down town,
We people on the pavement looked at him:
He was a gentleman from sole to crown,
Clean favored and imperially slim.

And he was always quietly arrayed
And he was always human when he talked,
But still he fluttered pulses when he said,
"Good-morning," and he glittered when he walked.

And he was rich—yes, richer than a king—
And admirably schooled in every grace:
In fine, we thought that he was everything
To make us wish that we were in his place.

So on we worked, and waited for the light,
And went without the meat and cursed the bread;
And Richard Cory, one calm summer night,
Went home and put a bullet through his head.