The speaker in this poem is a persistent observer. Seriously, this person, whoever it is, takes a long, hard look at this filling station, and spares us no details. She's practically Sherlockian in her observation skills.
She is also a little opinionated, if not downright judgmental. If we hear ewwwww, it's soooooo dirty again, we might just put her on a timeout for rudeness. But despite how nasty the speaker thinks the filling station is, she seems to be intrigued enough to look further into the place. She's not quite ready to write it off yet, so she checks out the porch, the doily, and other signs of home life.
By the end of the poem, while the speaker hasn't totally abandoned the "icky" rant, she has warmed slightly toward the place, and can see that there's some love underneath all that grit and grime. Which is nice, because it makes us feel like all in all, we're in pretty good hands with the speaker. She misses absolutely nothing, and takes us through each greasy moment.