...because you just might get it.
A character makes a wish and actually gets what they wished for, only to find that the reality does not live up to their fantasy.
This trope is all about how a character who makes a wish comes to regret it; the actual circumstances vary. The wisher may or may not have known that their wish was actually going to be heard. The one which grants it may be anything from a wish-granting Genie who wants to show the character the error of their ways to a Jackass Genie who just wants them to suffer. A sudden appearance by Louis Cypher, ready to offer a Deal with the Devil, is not out of the question either. Sometimes the character gets a tour through an Alternate Timeline. Other times the mechanism of the granted wish is not even explained — the wisher gets what they want through nothing more than an ironic and coincidental twist of circumstances.
The "deal breaker" that makes the wish not worth it also comes in a lot of possible flavors. Perhaps the character finds out that what they wanted comes at the cost of something they wanted even more. Maybe the element of their life that they wanted gone is really essential to who they are; maybe the wish isn't all they thought it was cracked up to be; or maybe it just comes true in an unanticipated manner.
In many cases the character repents of their ill-considered wish and things revert to normal, though in some stories the character is stuck in the new situation and forced to deal with the consequences of their thoughtless wish.
This is an elementary form of deconstruction — the character wants X, and then they find out that X has unforeseen consequences or is less satisfying than expected. Nine times of ten this is an outright Aesop, though strictly speaking it doesn't have to be. A crucial element of playing that angle well is making the "deal breaker" a meaningful, inherent flaw to the original wish rather than something tacked on or that could have easily turned out differently if the character had more common sense. Otherwise, a Broken Aesop is guaranteed.
Often a cause of Blessed with Suck, though not the only one; wont to count as an Opinion-Changing Dream; Contains the same type of irony as Ironic Hell. In some cases the experience may lead the wisher to discover an Awful Truth.
Sub-Trope of Be Careful What You Say. Super-Trope of It's a Wonderful Plot, I Wish It Were Real, I Wished You Were Dead, Please Dump Me, and Rhetorical Request Blunder. Often overlaps with Full-Circle Revolution — "So you want new leadership? Meet the New Boss, same as the old boss."
Compare Accidental Incantation (which covers magical spells), Gone Horribly Right (when science or logic is involved rather than wishes), Wanting Is Better Than Having (when getting your wish ends with more disappointment than satisfaction), Tempting Fate (which does not specifically require a wish) and Original Position Fallacy (when someone wants something they know will be bad for some, but wrongfully assume they will benefit from it).
Contrast the Literal Genie, which ignores the intent of the wish in favor of the exact words; this trope is about the complications that arise when you get exactly what you wanted, rather than exactly what you said. A Jackass Genie is likely to cause this to happen, if they don't just twist your words entirely. The Benevolent Genie, too, may make this happen if they think you "need" to learn the lesson from getting your wish, or if they lack the common sense or human perspective to see that the wish is disastrous, or if they're just constrained to grant the wish no matter how disastrous it is.
