The poem, "What happens to a dream deferred?" by Langston Hughes expresses what happens to the dream and the dreamer when one realizes that a great dream of theirs will never become a reality. I think a possibility is that the dream he was talking about was racial equality, considering the time period in which he was writing poetry. The first stanza, "Does it dry up/like a raisin in the sun?" means that the dream, along with the dreamers hopes, shrivel up and turn into something so meaningless and small that the dreamer knows it's there, but they don't care anymore. The second stanza, "Or fester like a sore--/and then run?" means that the dream stays in there for so long, nagging at the person, rotting in their mind, spreading an infection that affects every thing the person thinks, and runs beyond their thoughts into the way that they act.
The stanza after that, "Does it stink like rotten meat?" means that the dream becomes something undesirable, something that the dreamer does not want anymore, because it is just a lump of rotten meat, stinking up their mind, filling them with lofty expectations they know will not be filled. The stanza after that, "Or crust and sugar over--/like a syrupy sweet?" means that the dream may just stay in the dreamer's mind, like a pot of gold at the end of a rainbow. Beckoning out to them, and while a realistic part of their body may tell them that the dream can never be reached, the dream has developed a sugary coating so enticing, so protecting of the dream, that the dreamer cannot shake their burning desire to achieve their dream. The following stanza, "Maybe it just sags/like a heavy load," means the dream just hangs on a person's mind, not exactly "festering" in their mind, but just sitting on it. And the person realizes their dream will never be achieved, but it just stays their, weighing them down, probably making them feel depressed. The dreamer is constantly carrying a heavy weight that they cannot shake. The final stanza, "Or does it just explode?" means that reality and maybe society just comes down like a brick on a balloon, crushing the dream into oblivion. Killing it instantaneously, and the dreamer can do nothing, but look in shock at a dream that was there a second ago, but now is gone.