I make a distinction between manners and etiquette - manners as the principles, which are eternal and universal, etiquette as the particular rules which are arbitrary and different in different times, different situations, different cultures.

We are born charming fresh and spontaneous and must be civilized before we are fit to participate in society.

Society cannot exist without etiquette ... It never has, and until our own century, everybody knew that.

Charming villains have always had a decided social advantage over well-meaning people who chew with their mouths open.

people, in forming their opinions of others, are usually lazy enough to go by whatever is most obvious or whatever chance remark they happen to hear. So the best policy is to dictate to others the opinion you want them to have of you.

It is a widespread and firm belief among guests that their departure is always a matter of distress to their hosts, and that in order to indicate that they have been pleasantly entertained, they must demonstrate an extreme unwillingness to allow the entertainment to conclude. This is not necessarily true.

For email, the old postcard rule applies. Nobody else is supposed to read your postcards, but you'd be a fool if you wrote anything private on one.