Much depends on how we take the ending. When I first read it, I laughed out loud at the final line, and felt delighted at what I took for a trivial and charming little appreciation of motherhood. I mention that response because it may be a common one, and surely there is some truth to it. Bishop is a poet of great charm. But as we ponder the ending it gets more and more suggestive. "Somebody loves us all" – unless the poem’s evidence, namely a doily, a taboret, a begonia, and some neatly arranged cans of motor oil, doesn’t justify such an all-inclusiveness, so that the final line becomes ironic. We can read it with a sarcastic accent on somebody, as if to admit wryly that maybe somebody is fool enough to love even this oil-soaked father and his greasy sons.
… Indeed, Bishop’s work is preoccupied with motherhood, sometimes in the most unlikely places. … The unseen but much pointed to mother of "Filling station" thus seems part of a private obsession, perhaps unacknowledged, but still urgently felt as central to Bishop’s world.
For the final line of "Filling Station" turns to herself and turns to us all. The unexpected cropping up of first person plural at the end is part of what so greatly expands the poem’s final import, but in a way so gentle we can almost spoil it by pointing it out. She sustains the subtlety of what could have been a bravura pulling in of her readers by mixing it with that mysterious word somebody. The charmingly coy vagueness of that climactic reference monopolizes our attention, so that we take the effect of being brought in ourselves with hardly any notice. Which is partly the point, for the poem is about taking thins for granted. We take the work of women for granted, and that work, especially when it is the work of art, turns surreptitious in response. It gains something distinctive in that way, but loses much as well. It loses, in Bishop, some species of confidence, or else provides a specially feminine outlet for the crisis of confidence that any poet suffers. For no poet knows for sure where the next poem will come from, or whether it will come at all.
from Robert Dale Parker, "Bishop and the Weed of Poetic Invention," Chapter 1 in The Unbeliever: The Poetry of Elizabeth Bishop (Urbana: University of Illinois Press, 1988), 25, 27.