A dystopia is quite common as a literary subject. It is usually unpleasant, with a repressive society and/or strict ruling force, and is the flip side to another common literary subject; a utopian society, in which everything is perfect to either the inhabitants or/and protagonist.
Some stories set in a dystopian universe or 'world' may seem quite normal or maybe even 'perfect' at first, but eventually the reasons behind that become apparent and become quite unpleasant for the protagonist as they are forced to fight against a society or group they were once a part of.
Examples of this kind of dystopian world are in both Uglies [2005, Scott Westerfeld], where the reader follows the female protagonist, an 'ugly' who is allowed to undergo surgery to become 'pretty' -portrayed to be a perfect state in her world- once she turns sixteen, but over the course of the novel, she finds out it might not be everything she had hoped for. With mind manipulation by the ruling force, isolation between certain age groups until a 'coming of age ceremony' and bulling the 'inferior' group into wanting to do what the ruling force chooses- in Uglies, it is becoming a 'pretty' who has purposely been given brain damage without consent, something she does not want to happen
And in The Knife of Never Letting Go, which follows a very simular pattern. The main protagonist [Todd] is a 'boy', and will continue to be so until he is thirteen and has completed a 'coming of age' ceremony of his own, and from then on is considered a 'man'. Like in Uglies, becoming a 'man' is considered a perfect state, or at least more idyllic than being a 'boy', and this is reinforced by bulling by his 'superiors' -men- over his 'inferior' state, thus making it seem that becoming a 'man' is something he should want to become, so he is no longer isolated from his peers, and becomes 'one of the group'. Again, over the course of the novel, he finds out exactly what become a 'man' means, and