The Jargon File (version 4.4.7, 29 Dec 2003):

Right Thing
 n.

    That which is compellingly the correct or appropriate thing to use, do,
    say, etc. Often capitalized, always emphasized in speech as though
    capitalized. Use of this term often implies that in fact reasonable people
    may disagree. ?What's the right thing for LISP to do when it sees (mod a 0)
    ? Should it return a, or give a divide-by-0 error?? Oppose Wrong Thing.


The Free On-line Dictionary of Computing (30 December 2018):

Right Thing

   That which is *compellingly* the correct or appropriate thing
   to use, do, say, etc.  Always capitalised, always emphasised
   in speech as though capitalised.  Use of this term often
   implies that in fact reasonable people may disagree.  "What's
   the Right Thing for Lisp to do when it sees "(mod a 0)"?
   Should it return "a", or give a divide-by-0 error?"

   Opposite: Wrong Thing.

   [Jargon File]

   (1994-10-28)