In my mind, the most interesting element about this poem would be the imagery employed regarding death. Dickinson's conception of death through her mental pictures is not a pain- ridden or darkly malevolent force. Rather, it is akin to a warm bath, or something that is approachable. The word "kindly" helps to convey this tone in line 2, and the term "civility" in describing death's approach in line 8. The different settings that the speaker and death visit remind one of the joys of life, but also of its transitory nature. The implication is that these are all stages towards the inevitable force of death, something not to be feared, but viewed with a sense of embrace as it does the same to us.
In the first stanza, she is saying that she was too busy to slow down to die but she died anyway. In the second stanza, she is saying that she had to slow down. She had to stop working and stop having fun. Then she describes the places they passed by and what she saw there. (The reader of the poem realises what she lost when she died.) In the last stanza, she says that it has been centuries since she died. She realizes now that it will be forever, that she will be watching(immortality), but it feels like only one day.
Because I could not stop for Death,
He kindly stopped for me;
The carriage held but just ourselves
We slowly drove, he knew no haste,
And I had put away
My labor, and my leisure too,
For his civility.
We passed the school, where children strove
At recess, in the ring;
We passed the fields of gazing grain,
We passed the setting sun.
Or rather, he passed us;
The dews grew quivering and chill,
For only gossamer my gown,
My tippet only tulle.
We paused before a house that seemed
A swelling of the ground;
The roof was scarcely visible,
The cornice but a mound.
Since then 'tis centuries, and yet each
Feels shorter than the day
I first surmised the horses' heads
Were toward eternity.