I think everyone understands your being tired of someone's sponging. It's your burning hatred for such an innocuous signature that is bizarre.
:arated:
I think I've mentioned it already in this thread but a valediction is just that, a farewell. It's what's inside the body of an email/letter/missive that counts. Judging how someone chooses to say goodbye in any form of correspondence is like judging a book by its cover and not by the content.
Maybe I'm hopelessly pragmatic, but I couldn't give a fig how someone signs off in a message, I've got far too many other things to worry about.