A speaker punches a mirror because they hate their own reflection, then spends the rest of the poem circling around the consequences. The form does a lot of the work here. Each stanza picks up a line from the one before, so the poem loops back on itself and ends where it began: the speaker still needs a new mirror. That repetition feels like being stuck, replaying the same moment and the same excuses.
The most telling line is "or so I like to tell myself." The speaker calls the act "purely irrational," but that sounds like a way to avoid admitting the real cause, which is plain self-dislike. The tone is flat and almost casual, even a bit darkly funny, with the sore hand and the shopping errand treated like small inconveniences. Underneath, though, the mood is uneasy. The speaker is hurt, in pain, and unwilling to look at why, and the poem suggests they will probably end up facing another mirror.