If it's against state law, it's generally considered a breach of Etiquette.

Visiting the sick is supposed to exhibit such great virtue that there are some people determined to do it whether the sick like it or not. ... All visitors everywhere are supposed to make plans to depart if they observe their hosts visibly wilting or in pain, but this is especially true at hospitals.

Everybody's an art critic.

One of the big no-nos in cyberspace is that you do not go into a social activity, a chat group or something like that, and start advertising or selling things. This etiquette rule is an attempt to separate one's social life, which should be pure enjoyment and relaxation, from the pressures of work.

the obligation to express gratitude deepens with procrastination. The longer you wait, the more effusive must be the thanks.

The dinner table is the center for the teaching and practicing not just of table manners but of conversation, consideration, tolerance, family feeling, and just about all the other accomplishments of polite society except the minuet.

GENTLE READER: You, sir, are an anarchist, and Miss Manners is frightened to have anything to do with you. It is true that questioning the table manners of others is rude. But to overthrow the accepted conventions of society, on the flimsy grounds that you have found them silly, inefficient and discomforting, is a dangerous step toward destroying civilization.