Sir:

I should never have thought you capable of writing to me so impertinently as you have done. But
your letter is a true mirror of the meanness of your character, of which I have had already too
many proofs to my sorrow, and I am happy to avail myself of this opportunity to terminate a
disagreeable acquaintance.
Great! I think that perhaps I will have to use it !
But, please, which is the correct signature after such a letter? I know just
Sincerely yours
but it seems to me too friendly... I would like an ironic and harsh signature...
Any suggestion?
Ciao
Emanuela