The best card game in town has been busted up. Miss Manners has left with some terrific cards in her hand, and no opportunity to play them.

Such cards are bristol-board and have engraved on them one's name and, in the case of a woman or unmarried man, one's address. The game was to run about town, leaving them with everyone for purposes of welcoming, congradulating, condoling, thanking, taking leave of, or any other excuse for ringing other people's doorbells. Formal calling, when properly done, was a social form combining the maximum of effort with the minimum of communication. In its heyday, it got to the point that people had to turn it over to their servants -- one's chauffeur ran up to the door with the card while one sat in the automobile, to be told by the other person's butler that madam was not at home, while that lady peeked out from an upstairs window.

In its way, this was the perfect social event. Strange that it should have died out.

The custom survives mainly in the diplomatic corps, where the necessity of acknowledging one's colleagues, at posts where there may be well over a hundred missions, is believed to promote world peace, in that it keeps the diplomats from engaging in more active diplomacy.

For private individuals the card may still be used to enclose with flowers or presents, or to bear little messages, such as "Looking forward to Saturday," or to mark one's place in a book. There are those who say that the corners are excellent for dislodging luncheon remains from the teeth, but Miss Manners wouldn't know.

Naturally, only the very best engraved cards will do for any of these purposes. Women's cards should be 3 1/8 inches by 2 1/2 inches, give or take an eighth of an inch; and men's, oh, say, 3 1/4 by 1 5/8. Names and social titles are used, so that the sender looks friendly by crossing out the title in ink when the card is used.

Initials are never used on cards, and suffixes, such as junior, are spelled out in full. The card of a married woman or couple used his name, so that one can stare at "Mrs. Hendrik Thinglebottom" without realizing that behind it lies Sally Wretzle, the airline president.

In other words, these cards are uninformative, expensive, and useless. Miss Manners is extremely fond of them.

Her honest advice, however, to anyone tempted to order them is to invest, instead, in the comparatively new invention of the over-sized card, a non-folding version of what used to be called an "informal" card. The size should depend on the latest postal regulations, as the Postal Service hates little cards and keeps making rules demanding larger and larger mail. This card is engraved with the name or joint name in the top center and the addresses in smaller letters in the upper right corner. It has room on it for notes, invitations, and replies to these.

Smaller cards have become the tool of business people who want to give their names to new associates in a more formal way than a lapel buttom reading "HELLO! I'm Gerry, your waiter." However, most business people mistake the card for the resume, and try to cram on it such details as telex address, telephone numbers of four branch offices, and the company's motto and logo.

The proper business card contains only the person's name, title, company name, one address and one telephone number. This is quite as much as anyone needs to know about a stranger before deciding whether to extend the relationship.

Besides, cards with too much engraving all over them make messy bookmarks.

MISS MANNERS RESPONDS

Q: My boyfriend and I are having an argument about what the response should be when someone says, "I love you." He once replied, "Thank you," and I said that one does not say "Thank you" when someone says "I love you." aWhat can one say in response besides, "I love you, too"?

A: There is no doubt that "I love you, too," is the only really acceptable reply to "I love you." Acceptable to the lover, that it.

However, making the other person feel good is not, as Miss Manners keeps telling you, always the object of etiquette. If you do not love the person making the original statement, replying kindly could lead to all sorts of dreadful complications, not the least of which is further and even more unfortunate questions, such as "But do you really love me?" or "More than you've ever loved anyone before?" or "How can I believe you?"

One needs, therefore, to make the lack of reciprocations clear while showing gratitude for the other person's good taste. Your boyfriend's suggestion is not bad, although Miss Manners prefers, "You do me great honor."

If, however, his object was merely to give variety to the conversation of happy lovers, "Thank you" is a little stiff, as it is firmly attached in most people's minds to "You're welcome," and that has a kind of finality that rounds off the conversastion, rather than leading it to "Let's run off to Paris for the weekend."

If he doesn't want to keep saying, "I love you, too," let him offer one of the many re-statements of this remark in every true lover's icky vocabulary.

But Miss Manners has never understood why lovers can't keep saying the same thing over and over. They keep doing the same thing over and over, don't they?

Q: Is it now considered appropriate for everyone to address everyone else by first names, without even asking permission? Is this no longer considered taking a liberty?

In the past few months, my insurance salesman, a man who sold me a car part, and a man who sold me a pair of shoes, have all considered it their privilege to address me by my first name. My name is on my credit cards, etc. and cannot be kept from the world. I am about to leave the military (where am addressed by my rank) and enter the civilian world. How do I inform people, particularly prospective employers, that I do not wish to be addressed in this manner, without appearing rude myself?

I am not from a bygone age. I am 26, and appalled by this new rudeness, which passes for casualness or friendliness. Please help.

A: The answer to your question is, Miss Manners regrets to say, that yes, indeed, it has become commonplace to use first names promiscuously. The answer to your plea for help, however, is that yes, we will fight this unfortunate practice together, with whomever else cares to join this noble cause.

Such usage is not only undignified, but makes a sham of the idea of friendship and equality. There is no such thing as instant intimacy.

As you recognize, the ticklish part of the fight for good manners is to exhibit them oneself during battle. One cannot go around correcting others.

But one can go about driving others crazy in a perfectly polite fashion.

One method of doing this is to keep saying, "No, no, I'm terribly sorry, you must have misunderstood -- George is my first name. My last name is Pinkerton. Another is to address the offenders by their last names, no matter how many times they urge you not to. If they only tell you a first name, or say, "Call me Sam," then address that person as "Mr. Sam."

Miss Manners is not guaranteeing that this will teach others respect, but it will pay back some of the irritation you have experienced and serve to alert them that something is wrong, even if they can't figure out what.