Emanuela: Re: "uncomplimentary closings" The possibilities for uncomplimentary closings are virtually endless and can run the full ranges suggested in this post. A fairly simple, rather mild example might be -- " I trust that even you, Mr. /Ms ----, can understand the full import of the foregoing and can further understand that, in such circumstances, I now remain, and ever shall quite happily remain so,
Your former acquaintance,"

zzzzzzzzzzzzz"
This is a mild and understated version. These are great fun to write. In those glorious days of epistolary communication ( of which Sparteye's letters are an example), before the tel and tech inventions, the complimentary (or UNcomp...) close was itself a minor art form, and a fertile field for making that final, clever, memorable point, whatever its nature.