Where does the phrase 'come unstuck' derive from? And why does it mean the opposite of how it sounds (surely if you come 'unstuck' then you're not stuck anymore)?
The 'unstuck' element here is based on the idea that to be 'stuck together', as it were, means to be 'done up/fastened/in control' etc. Consequently, to 'come unstuck' means to fall to pieces or become disintegrated...ie come to grief or fail.