``I could not send mail to you, there was an error message.''
``What email client do you use?''
``Foo Mail 1.0 for the Bar Operating System.''
``Ah, I see. This mailer creates broken email; my mail server rejects
them because they are broken.'' (Optional: ``You have to set the
option foo to make it bejave correctly.'')
``But I can send email to anyone else!''
Note that this assumes that both users have a knowledge beyond that of
the average user and far beyond that of a user who writes his text below
the signature ``because you put the letterhead on the top, don't you?''
what should happen is that the sender gets a message back that says:
Your message could not be delivered because it was illegally formatted.
You should replace your mail reader with one that works correctly.
See http://foo.bar/mail-readers.html for a list of broken mail readers.
of course, that still won't help users who think that if Microsoft makes it,
it must be fine. then again, such people deserve to lose.