Everything in "Glass" is measured by someone else's gaze. The first stanza is crowded with words of seeing: the speaker wants never "to look bad in your vision" and keeps "failing in your eyes." The "you" is never named. It could be a parent, a friend or a partner, and the poem doesn't say, which lets the addressee loom larger than any one person could. The opening line, "You were always such an important person in my life," is in the past tense, while the failing happens in the present. The poem hints at a bond that has cooled, or one that has never stopped hurting, but it never explains which.
The second stanza turns the blame inward. "Maybe it's because I'm too sensitive" is hedged and apologetic, and the word "normal" arrives for the first time: "A normal person could bear this much easily." The stanza ends on "but why not me?", a four-word line with a lowercase "but" that sounds like a voice trailing off. After the long, sprawling lines before it, the shortness feels like a drop. The poem has no regular rhyme or metre, and its lines are uneven. Punctuation is loose, with many lines running on without a stop. Only the last line of each stanza closes with a full stop or question mark, so each stanza reads as one sustained thought that finally runs out of breath.
In the third stanza the speaker looks up and outward, accusing a "cruel god or goddess" of a "sickish joke." The word "sickish" is slightly off-kilter, closer to bitter speech than to polished poetry, and that roughness makes the anger convincing. The verb "cast" is worth noticing. Judging by the imagery, it might connect to glass being cast in a mould, and also to actors being cast in roles, which prepares for the masks to come. The best image here is "The normal look down at the ones of same height." If everyone stands at the same height, there is nothing to look down from, so the hierarchy is shown to be invented. It rests on "one uncontrolled difference," which the poem deliberately leaves unnamed. That vagueness lets readers fill in their own version, and it suggests how a single trait can be treated as a person's whole identity.
The title word holds back until the last stanza, where the speaker carries a "people pleasing glass heart." Glass is fragile, but it is also transparent, which makes it an odd thing to hide. That is the irony of the stanza: the speaker puts masks over something that is see-through and already "cracked." "Cracked wounds" blends two kinds of damage, a window that splinters and skin that bleeds, so the heart is both an object and a body. The participle "Thinking" in "Thinking masks can heal" suggests the speaker doubts this. A mask can hide a crack, but nothing about it mends one.
The last line, "Just for the appreciation I get from you," ends on the word the poem began with. The opening line starts with "You" and the closing line ends with it, so the speaker is framed by the other person on both sides. "Just" can mean "only," which makes the reward sound small, or "merely," which makes the whole effort sound a little absurd. There is also a puzzle between the first and last stanzas. The speaker keeps failing "in your eyes" yet still receives "appreciation." One reading is that approval arrives only occasionally, and only when the mask is on. That is an inference from the text, but it would explain why the habit is so hard to break.
The poem's significance lies in how plainly it names a common experience, the exhausting work of earning acceptance by being less than yourself. It moves from self-blame to cosmic complaint to daily routine and offers no rescue at the end. A neater poem might have added a moment of recovery, but this one stays with the ache, and that honesty makes it credible. It also shows how one sustained metaphor can carry an argument. If the heart is glass, the poem asks who is holding it, and why that person's opinion should decide whether it breaks.