* ''{{Urinetown}}'' ends with the heroes triumphantly toppling the [[CorruptCorporateExecutive evil toilet monopoly]] and launching a new era of free urination. Only, as it turns out, the monopoly was right about the water shortage, the newly unrestricted flushing makes the town run dry, and almost everyone dies of thirst.
-->'''Little Sally''': What kind of a musical is this?! The good guys finally take over and then everything starts falling apart?!\\
'''Lockstock''': Like I said, Little Sally, this isn't a happy musical.\\
'''Little Sally''': [[SoundtrackDissonance But the music's so happy!]]\\
'''Lockstock''': Yes, Little Sally. Yes, it is.
** Hail Malthus!
* ''[[Creator/HenrikIbsen The Wild Duck]]'' Nice job telling your friend his family's been lying to him all these years. [[spoiler: And now his daughter's dead]].
* ''Theatre/{{Wicked}}'' finds Elphaba listing her contributions to this trope in the song "No Good Deed".
* ''Theatre/SweeneyToddTheDemonBarberOfFleetStreet'': If Anthony Hope didn't bust in Sweeney's barber shop in the midst of his shaving of Judge Turpin, his plans to rescue Johanna Barker would have gone according to plan, and Sweeney himself wouldn't have gone off the deep end due to being denied his first shot at revenge.
* ''Theatre/{{Macbeth}}'' - Macbeth and Banquo hear the witches predictions that Macbeth will become Thane of Cawdor, then King; and Banquo will become the father of kings. Immediately afterwards, Macbeth is awarded the title of Thane of Cawdor due to the previous Thane turning traitor and Macbeth successfully fighting the resulting invasion. Macbeth is happy with his battlefield promotion, and thinks that becoming King will fall into his lap as easily - but Lady Macbeth goads him into murdering the King to take the throne instead. And then murder the King's guards after pinning the crime on them. And then try to murder Banquo and his entire family so that he won't father kings...which leads to Macbeth murdering everyone in sight and bringing his downfall.
* In the 2007 film adaption of ''{{Hairspray}}'', when Tracy participates in the march and hits a cop on the head with her sign and runs away, it gives Velma a good opportunity to stop Tracy from participating in the pageant by having the same police guard the entrance,[[spoiler: making Tracy and the others devise a plan to sneak into the pageant. If Tracy had been bailed out along with Maybelle, she wouldn't have had to hide from the cops and sneak into the pageant!]]

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