ACCEPTING a present graciously is not much of a problem when the present turns out to be tickets for a Carribbean vacation. In that case, Miss Manners trusts you to emit the proper cries of surprise and joy, to place your hands over your face in the classic posture and to confuse, in your expressions of gratitude, the attractions of the gift with those of the giver.

But what if the surprise is not of the pleasant variety? Can Miss Manners trust you to behave properly when given a present that dissappoints you?

From greediest childhood, we build up so many expectations about Christmas presents that the chances of being let down are statistically higher than those of feeling unworthy of the bounty showered upon us.

You can guess, of course, that Miss Manners' general rule in such instances is to fake the reaction she has described for you in detail. The ability to look delighted when not -- now that is truly a gift.

You should, of course, modify this until it is plausible. But Miss Manners will also allow a form of, shall we say, constrained delight, to be used in cases where it is possible to warn the giver, without outright hurting of feelings, that more care another time might produce a better result.

This reaction consists of a wide smile made with closed lips, and accompanied by a bright-eyed but sober look. The words are, "why how nice!"

Promise Miss Manners that you will not employ this to encourage more expensive presents -- only more appropriate ones. And even then, only when the thought counts against it.

Here is a brief guide to disappointing presents, with notations as to which deserve unrestrained gratitude, and which constrained gratitude: Useless Presents

Constrained: silver cigarette case from longtime lover to person who has never smoked, especially if engraved with wrong initials.

Unrestrained: hand-made ceramic ashtray from child to non-smoking parent. Useful Presents

Constrained: equipment for baking bread at home to mother who has just re-entered job market.

Unrestrained: crockpot to ditto, who had hoped for attache case. Tasteless Presents

Unrestrained: knitted toilet seat cover from person who has knitted covers for all own toilets. Tasteful Presents

Constrained: Coffee table book on antiques from person with formal old house to one who has glass house with high tech furniture. Unacceptable Presents

Furs, jewelry, yachts from person one doesn't know very well.

This calls for a third response. The mouth curves in a half-smile of regret before and after the protest, but the eyes shine luminously. MISS MANNERS RESPONDS

Q. My husband and I have been happily married for the past three years. From time to time during those years, my husband's past lady friend has attempted to see my husband. She calls him at the office, and this time came to our home. Fortunately, we were not at home, but our son told us of her visit. My husband tells me he has tried to discourage her by not accepting any invitations and by not coming through too friendly over the phone. He tells me that breaking up with her was like being cured of a "cancer." Also, there are some incidents he would rather forget, but she continues to attempt to keep in touch. She lives out of town, but every time she is here, she makes a point to contact him. I would like your suggestion on how we can get rid of her permanently.

A. The category of etiquette in which you will find the solution to this problem is known, to Miss Manners at least, as Killing with Kindness.Miss Manners, who never believes in being rude, thoroughly believes in the sort of politeness that can drive people away.

Here is a sample of what you can do in this case:

Your husband invites the lady to lunch in a nice restaurant. He meets her there, at a table oddly laid for three. He only half pays attention to her greetings, because he keeps looking at the door and his watch. You arrive. Your husband leaps up from the table, his face alight with pride, and greets you profusely. You greet the lady with enthusiasm and warmth, and say how glad you are to meet her, that your husband had been urging it for sometime, and you are both so anxious to hear how she is getting along these days.

During the luncheon, you both keep encouraging her to talk about herself while you listen with rapt attention, only occasionally showing embarrassment when you catch yourself giggling together over a private joke or absently touching fingers on the table or feet under it.

One such lunch should do it.

Q. Can you set some guidelines for the communal use of opera glasses? Here is the situation:

For two years now we have had a ballet subscription with two other couples. We have tickets with them again this year, but I dread it because of the commotion that goes on when glasses are passed across our row.

My husband has a pair of field glasses that give you an incredibly close view -- too close for my taste for watching dance, but you do get a perfect look at the star's face, sweat and makeup and all. I don't use them except sometimes during a curtain call as it annoys me to have parts of the body cut off.

One of the other women has a pair of pearl-handled glasses on a stick that she is always flourishing about. They look elegant, but the view is like peering through a submarine periscope, and a dirty one at that. The man from the other couple has a pair of cheap glasses that magnify a little but not enough to make it worthwhile.

So, you see, we are six people with three pairs of glasses. And once a man sitting next to my husband, a stranger not in our party, even asked to use his glasses.

But what drives me crazy is all the whispering this involves. Someone in our group is always saying, "do you want these?" or reaching across and saying, "Can I use those?" The worst is when the people who don't have glasses ask which ones they're being offered and decide that no, they want my husband's strong ones, for instance, and not the fancy useless ones.

We have been shushed by others more than once, and I can't bear it myself. Can you make any suggestions as to how to handle this quietly?

A: 1) Give the two glasses-less people opera glasses for Christmas or hint to their spouses that you know that is what they would like. (The latter is cheaper.)

2) Take up mime. Pat an arm when you want glasses, and wave one hand toward the offer when you want to refuse it.

3) Get closer seats.

4) Reply "WHAT?" when offered glasses, thus provoking a nearby stranger (not the one who wanted the glasses) to tell your party in no uncertain terms to shut up.

Q: I certainly agree that it is vulgar to wear "designer initials or their names on your clothes, particularly as some of these people sell franchises, and no more designed the clothes than I did. I do like, in contrast, the effect of having my own initials, or monogram, on my things. Could you tell me, please, where -- that is, on what items of clothing -- it is considered tasteful to have these?

A: It is faultless to have your initials or your entire name, on the lining of your sable coat, embroidered in the same color of thread as the lining. Initials may also be put on handkerchiefs and leather goods. A servant girl who has married into the peerage is excused if she wants to have a coronet embroidered on their underpants.

Q: At a beautiful engagement party, which we gave for our daughter and her fiance, they went around telling all our friends that they never plan to have children. We were horrified. It isn't that we don't understand that they are young (22 and 23) and maybe shouldn't have children for quite a while; and it isn't that we're anxious for them to provide us with grandchildren. (Our other daughter has three children and our son has four, so we can hardly keep up with the birthdays and the visits and the babysitting as it is.) We just think their statement was in poor taste. If they do have children, those children are going to think they were unwanted. Also, what must our frineds at the party have thought of such a declaration?

A: It is never charming to announce your reproductive plans socially, but Miss Manners does not think that your friends will remember the statement with anything except amusement should the couple later change their minds. Didn't your daughter announce to you, a decade or two ago, that she was never going to get married because boys were so icky?