The figures of speech come in a series of lengths of time. The poet would happily wait for her lover, IF she knew that the time of waiting would come to an end. If he were coming in the fall, she'd brush the time away easily. If he were coming in a year, she would wind the months like balls of yarn and put them away for safe keeping. Even if he were coming centuries from now, she'd count off the time on her fingers although they might become skeletal fingers by then. (Dickinson is always the realistic. She looks at things the way they are.) If he were not coming till her super-extended life were over, she'd leap into Eternity with him and throw her mortal life away like a watermelon rind. BUT--and here is the structural joint at the poem's core--she does not know when or even if he will ever come to her. That lack of closure, that uncertainty, "bugs" her (pun). She feels as she would feel when a bee lands on her and has not yet stung her but will any second.
This is a great love poem.
I think that the examples of figurative language help to bring out the juxtaposition of the conditional and the real that exists in Dickinson's poem. If we simply consider the poem told from the point of view of someone who waits for another, there is compassion already embedded. The poem works perfectly for a loved one waiting for another. There is compassion in this because all of us have waited for someone to return from a long absence. Certainly, this premise is enhanced with the use of "If" statements, statements of conditionality. In this, Dickinson uses figurative language such as "the months in balls," almost to suggest the need to bounce such time away in the hopes of reconciliation. Another similar example would be the use of the "housewives" who swat a fly, almost indicating that if there was a guarantee of a loved one returning, time could be dismissed in the same way. These examples of figurative language help to bring out a sense of compassion and yearning in the speaker, instantly connecting to another. The ending metaphor of the sting of the bee reflects the reality, a condition in which time exists and time cannot be dismissed. The only certainty is waiting and this becomes the pain that undercuts all other hopes of the conditions. This "sting" is one that creates an understanding in the reader. Compassion is evident for the death of hope is a painful predicament.