Whenever we read, we impose our own perspective onto what the writer has written.
As a result of this it becomes even more necessary to apply the elements of the story- as it is written- so that the true tale is not lost.
If we are aware of the importance of the setting to the story, it helps to keep the context as intended. By knowing and understanding what elements are incorporated into a story- the literary elements- it helps us to feel the story and be aware of the subtle nuances which add to the atmosphere.
Sometimes it is easy to overlook elements such as sound and sight, while at other times the imagery comes through so vividly from the author's choice of words. Everyone can call to mind a particular phrase that evokes an image, something that speaks to you individually and lingers long after the rest of the story fades away.
Also, recognizing the perspective of the narrator is key to understanding the work as a whole. Should the author choose a perspective which does not necessarily make the reader feel that there is a cohesiveness, it is good to be able to recognize the shift in perspectives.