Annoying letters with annoying errors

Do you ever parse a letter you receive?

It's annoying when large corporations give the impression in correspondence that they are on familiar terms with the addressee. 

It's also annoying when people use terms of endearment, when you know well they don't mean a word of it.

How do you deal with errors of grammar and syntax, especially in letters that are annoying?

David Hanly of 'Morning Ireland' fame, when working on the programme, always insisted that no presenter on his programme would ever use the word presently incorrectly.

It's part of Hanly's legacy that RTE always uses presently correctly.

Presently, in these parts of the world, means in the immediate future and does not mean currently or at present.

The dogs in the street know that the word number takes the singular.

There is often an interesting  link between the use of uppercase letters and the self-importance of the writer.

Eats, Shoots & Leaves by Lynne Truss comes highly recommended to anyone, who is a regular letter writer, as does Alex Games' Balderdash & Piffle.

Any organisation worth its salt would have a house style-guide.