The first line in the song, "We said some things we didn't mean," immediately conveys that an argument took place. "From where we're standing I think we both know/ maybe we're better off alone," in the same stanza, leads the audience to the conclusion that the relationship is on the verge of ending.
One of the most multidimensional words, however, occurs in the lines, "Under the bridge on castle street/ We wrote our names in the concrete." In these lines, you have a visual of names literally written in wet cement. Nonetheless, concrete, as an adjective, can also mean "constituting an actual thing or instance; real." By saying that their names written together are in concrete is implying that the embodiment of their relationship is hard, enduring and real.
The chorus begins with, "We got fire on our tongues." The fire on their tongues signifies the hurtful words the couple have exchanged. "Fire" in this line is another example of a multidimensional word: fire symbolizes the burning arguments and the pain inflicted by their impact on the aggressors. The next line, "We got no air left in our lungs," gives the listener the feeling of breathless exhaustion, similar to situation of ceaseless and cyclical disputes.
The most powerful line in the entire song reads, "And all that's left is skin and bone." When the listener is immersed in this line, they imagine a moribund body of decaying skin and bone. The body, lacking its heart and life, symbolizes the wearisome relationship.
Even the end to this masterful song is notable. Lewis finishes "castle street" with the same lines it started with, "We said some things we didn't mean/ With us there is no in-between." The structure of the song foreshadows the outcome of the relationship: the couple is stuck in the repetitive cycle of conflict just like circular lyrics of the song.