IF THE sociey were not in a state of Etiquette Emergency, Miss Manners would not attempt to meddle with the ritual of the New Year's Resolution. She finds it sweet to hear people annually resolve to lost 10 pounds and clean their desks -- the air of modest moral struggle this lends to the first three days of every January is charming. But times of crisis call for sacrifice. The national rudeness level has reached dangerous proportions. Each citizen has to commit himself or herself to behaving himself or herself, or we will all soon be committed.

The situation, as Miss Manners sees it, arose from just the spirit of improvement that leads people to the excellent resolves associated with the beginning of a fresh year. There is a mistaken notion abroad that if one does one's best, one may be intolerant of those who do less.

Say you have given up smoking. Naturally, you will take the occasion to be grumpy and irritable in the bosom of your family. If you have stored up some personal credit there, through years of smoking cheerfulness, they may accept this good-naturedly for a short while. If it ends there, Miss Manners has no objection.

However, the successful non-smoker will then go on to attack perfect strangers or, rather, imperfect strangers who smoke. If this were done politely, Miss Manners would still have no objection. The confinement of smoky air to the immediate and private vicinity of smoke producers is a valid goal.

But what Miss Manner sees is an atmosphere polluted with self-righteous insults. Non-smokers, joggers, food purists and other such improved products feel they have license to chastise the world.

Worse are the people who have had general self-overhauls, rather than specific repair jobs. Those who have newly discovered their personal worth through therapy, assertiveness training or other odd religious sects often become public menaces. Their friendly behavior is to point out that you are in bad shape, a fact only confirmed by your failure to realize this; watch out for their unfriendly behavior.

From a society that must once have been, by its own testimony, dedpressed, frightened and ridden with bad habits, we have evolved into a healthy, confident people who are impossible to live with.

Commands are barked at strangers. A person who is offensive to someone else, whether on purpose or accidentally, is viciously reprimanded.

These attacks, in turn, inspire counterattacks. It is not unusual for a mere peccadillo -- an accidental push in a crowded bus, some harmless hesitation on the part of an automobile driver -- to result in the exchange of screamed obscenities.

This is dreadful. People who do no wrong are making the world unbearable for normal people.

Miss Manners asks that this year, each person make it a New Year's resolution to be responsible for his own behavior and worry less about that of others. If correcting is imperative, she asks that it be done with gentleness and humility. If everyone refuses to engage in verbal combat, hostilities will soon cease. Miss Manners Responds

Q: I am seeing a young man -- how shall I say? -- intimately, but not yet necessarily seriously. Do you understand me? I would not be sorry if it turned out to develop into something permanent, but we are not at that stage at the moment. At any rate, he has now had me twice to visit his parents, who have been very lovely to me. I am fond of them quite aside from my relationship with their son, and am grateful for their warm hospitality. In writing them thank-you notes, I would like to express my affection but I am afraid that if I signed my letters "affectionately" or "love," they might get the idea that I am presuming on the relationship -- that I, in other words, have expectations of coming into the family. This would not be a good idea to plant at this time. How about "cordially?"

A: Please, no. "Cordially" in a letter closing is a word that Miss Manners and other authorities before her dislike. In the 1922 Emily Post manual, it is singled out as being a "coined" word that is both "condescending" and "pretentious."

Conventions were invented specifically to allow a person to retreat from originality in situations open to misinterpretation. "Sincerely yours" is a perfectly good closing, neither cold nor warm. Miss Manners quite agrees that this is not the time to suggest that you feel like a daughter to these people, and she would rather see you err on the side of formality than of intimacy. Cordially yours . . .

Q: We are three brothers and a sister whose mother is now living without marriage with a man who has some good qualities. However, we all feel that he is below her socially. He goes around the house in his undershirt -- that kind of thing. How can we tell her tactfully?

A: Tell her what? That her gentleman friend doesn't have a shirt on? She knows, she knows.

In the course of growing up, did you or your brothers or sister ever bring home a person you cared about who could perhaps not have seemed to your mother to be exactly what she might have wished for you as a partner? Did you mother ever indicate such a feeling? Probably not. If she did you would have replied, with high indignation, "I don't care, she's my friend and I'll choose my own friends, and I don't care about what you think of their clothes," or whatever.

Perhaps your mother is old enough to choose her own firends.

Q: I received a fill-in type invitation for a dinner, in which whoever sent it filled in the date, the time and the place, adding, "Please let us know if you will bring a friend." There was no place for filling in the name of the people issuing the invitation, and they didn't. How can I answer an invitation when I don't know who it's from?

A: Perhaps it's a surprise party. Perhaps this should teach us the danger of filling out forms, rather than taking the trouble to write out what we wish to say. As you have the address, why don't you write back, "Please let me know who you are."

Q: I recently got married and received between 250 and 300 gifts; 250 or more were money, so I had pre-printed thank-you notes made and sent them out. A few family members felt that I should have written in each and every one to thank them exactly what was given. This meant that I was supposed to write thank you for X number of dollars. I felt that this was in poor taste. Who is right?

A: Nobody. Everybody is wrong.

You are wrong, because you should have written each person a letter. It's a lot of work, and might take you a whille, but if someone has taken the trouble to write you a check, you can take the trouble to write that person a letter.

Your family is wrong about having to mention the sum. Any amount that is sent as a present is referred to in the thank-you letter as "your generous present." Over $100, you might make it, "Your very generous present."

Q: I do not consider myself to be a promiscuous person, but recently, much to my dismay, I learned that I have contracted a social disease. The man from whom I received this dubious honor was a passive carrier, so he was unaware of his condition. Since he is not from the area, I called him to inform him of the problem since I only see him infrequently.Is it wrong to expect some kind gesture from him? Maybe some get-well flowers or even a note? I'm not sure how modern etiquette would deal with this situation.

A: Modern etiquette does not have a specific rule to cover the social situation you mention, but it is Miss Manner's experience that traditional etiquette has a rule for everything. The one that applies here is that a note or flower or both would be a charming way to apologize for having inadvertantly caused another person discomfort.