Source : Free On-Line Dictionary of Computing

Unix brain damage
     
        Something that has to be done to break a network program
        (typically a mailer) on a non-{Unix} system so that it will
        interoperate with Unix systems.  The hack may qualify as "Unix
        brain damage" if the program conforms to published {standard}s
        and the {Unix} program in question does not.  Unix brain
        damage happens because it is much easier for other (minority)
        systems to change their ways to match non-conforming behaviour
        than it is to change all the hundreds of thousands of Unix
        systems out there.
     
        An example of Unix brain damage is a {kluge} in a mail server
        to recognise bare line feed (the Unix newline) as an
        equivalent form to the Internet standard newline, which is a
        carriage return followed by a line feed.  Such things can make
        even a hardened {jock} weep.
     
        [{Jargon File}]