There's a long list of thing that annoy the Wolf. Of course, many of us really enjoy annoying the Wolf. It's almost a calling for some of us.
My favorite is "Thou Shalt Never Refer to an Ebook Reader as an "E-Reader" Lest Ye be Smited Severely About the Head."
So .... we now add "Thou Shalt Never Place the Name of a Weekday in the Subject Line of Thy Posts, For Verily, That is the Work of the Devil."