Source : Free On-Line Dictionary of Computing

Wrong Thing
     
         A design, action, or decision that is clearly
        incorrect or inappropriate.  Often capitalised; always
        emphasised in speech as if capitalised.  The opposite of the
        {Right Thing}; more generally, anything that is not the Right
        Thing.  In cases where "the good is the enemy of the best",
        the merely good - although good - is nevertheless the Wrong
        Thing. "In C, the default is for module-level declarations to
        be visible everywhere, rather than just within the module.
        This is clearly the Wrong Thing."
     
        [{Jargon File}]