I thought there might be some neat ideas for letter subjects or ways that letter writers might tap into a good response from a letter recipient.
Barring these things, it was interesting to see that Crane is, perhaps trying to appeal to a younger generation. Unfortunately, it would seem that is done by using expletives and communicating like a teenager.
In the preface to this, while defining the origin of the word etiquette, (which was delightfully interesting) the concept itself was eschewed for being out of date, and anything-goes was the replacement. At least Infante cast a positive light on thank yous and how meaningful a letter can be to the one who receives it.