In olden times, [[InnocentBystander ordinary people]] would be very careful what they said because words have power. You didn't have to be a priest, oracle or wizard to cast spells with words, anyone, ''anyone'' could potentially [[RealityWarper make something happen just by saying so]].

The reasons are both supernatural and mundane. Lending weight to the proverb "you're only as good as your word", you have [[IGaveMyWord an obligation to follow through on your promises]], lest you face [[TheOathBreaker social]] (or even [[MagicallyBindingContract supernatural]]) consequences. This is why there is nothing more dangerous than making [[ThePromise promises]] lightly (even [[ImpossibleTask impossible ones]]). Firstly, some fool hero ''will'' complete the task and since your word is binding you'll be compelled to keep your promise. The other is because you are ''never'' alone... someone or some''[[TheFairFolk thing]]'' will be listening, and may well decide to give you [[BeCarefulWhatYouWishFor exactly what you wish for]]. More than one such tales starts because someone said something they shouldn't have, or started making [[DisproportionateRetribution very]] [[BreakTheHaughty ill advised]] [[{{Pride}} boasts]].

Speaking in the heat of the moment is doubly dangerous, it's not uncommon for {{Curse}}s to be cast this way to everyone's sorrow.

At the same time and on the other end of the spectrum, taking a vow of silence and undertaking some task or penance can break a curse.

SuperTrope to:
* AdviceBackfire
* BeCarefulWhatYouWishFor
* BlackSpeech
* IKnowYourTrueName
* LiteralGenie
* ThePromise
* RhetoricalRequestBlunder
* TheScottishTrope
* SpeakOfTheDevil
* TemptingFate
* ThreatBackfire
* WordsCanBreakMyBones
* WordPower

!!Examples not otherwise included in a subtrope:

[[AC: Comics]]
* In a spin-off book of the ''ComicBook/{{WITCH}}'' comics, Taranee's brother, who's been spending lots of time with his girlfriend instead of her, ends up showing up much too late to see a basket game with her favorite team like he promised. She refuses to buy his (heavily implied to be true) excuses about car trouble and snaps that she wishes he'd just disappear. She immediately regrets those words because, as a Guardian of the Veil, her words have ''a lot'' of power.

[[AC:Fairy Tales]]
* In ''Literature/JesperWhoHerdedTheHares'', Jesper's brothers lied about what they were carrying to the old woman. They thought. When they got to the castle, they found they were carrying what they had said.
* In ''Literature/WhuppityStoorie'', the woman says she will give the green gentlewoman anything she wants in return for saving her pig. What she wants, it turns out, is the baby.

* ExactWords in Johnny Rivers' "Secret Agent Man." The following line? "You'll give yourself away."

[[AC:Web Original]]
* At some point in ''Series/{{Noob}}'' [[CasanovaWannabe Valentin]] tries to pick up a girl in {{MMORPG}} by telling her "I bet you're a bomb in real life". The girl in question is a MadBomber in-game, and not interested at all.

* In ''Webcomic/{{Sinfest}}'', [[ don't actually read]] [[ the words Fuchsia found in Boogle]]. They've got power.