DEAR ABBY: I am the manager of a women's clothing boutique in a small, upper-class community. My staff and I have a problem with a customer who shops in our store almost weekly. She will purchase $300 worth of merchandise, only to return it all the next day, putting a huge debt in our register that can ruin our daily totals. These returns also cost the store owner a substantial processing fee, as all transactions do.

We have tried not assisting her while she shops, hoping to cut back on her purchases, but it hasn't helped. The woman will occasionally keep a piece or two, but not often.

There is the possibility that she recommends our store to her friends. We're a rather small but successful chain that caters to our ladies, but we simply can't afford to continue the relationship with this obvious compulsive shopper. We also do not want to make a scene by confronting her in the store.

We are all, the owner included, at a loss as to what to do. Should we continue to allow her to wreak havoc on our sales records? Please help. -- IN SALES IN LA JOLLA, CALIF.

DEAR IN SALES: Yours is a common problem in retailing. However, there are two ways to deal with it: First, insist that she pay for merchandise in cash only. Second, do not refund her money for items she returns; instead, issue her a store credit -- a voucher that is valid only in your store.

DEAR ABBY: Our 29-year-old son married a beautiful girl about six years ago. We noticed before their marriage that she never said "thank you" when something was done for her, or when gifts were given to her. (We didn't feel we were in a position to say anything, but we tried to set an example by voicing appreciation when they -- or anyone else -- did something nice for us.)

Now, however, our son seems to have acquired the same behavior, and it's very disturbing because he was raised to be courteous and appreciative. When either one receives a gift, they look at it, may say something like, "Oh, where did you get this?" or more often than not, say nothing, and they just put it aside.

Abby, we don't give strange or odd gifts. The items they have received from us are either displayed in their apartment or worn.

Isn't it reasonable to expect a "thank you" or at least, "This is nice, I like it"? We'd like to say something to them without hurting their feelings, but are not certain what that should be. What are your thoughts on this? -- PERPLEXED PARENTS

DEAR PERPLEXED PARENTS: Ask your son privately why his wife does not acknowledge your gifts. She may not have been taught that it's common courtesy to express gratitude. It's time someone taught her -- and your son should gently set her straight.

Advise him that it is discouraging to spend time, effort and money on a gift that goes unacknowledged.

DEAR READERS: A tip to travelers: Do not pack your medication in your luggage -- keep it on your person. Luggage does not always arrive when you do. If you boarded late, your luggage could arrive on a later flight, or possibly the next day. And never, never pack your jewelry in your luggage -- carry it on your person.

For an excellent guide to becoming a better conversationalist and a more attractive person, order "How to Be Popular." Send a business-sized, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby Popularity Booklet, P.O. Box 447, Mount Morris, Ill. 61054-0447. (Postage is included.)

DEAR ABBY: If my husband knew I was writing to you, he'd swear I was nuts. But I have a problem I have never seen addressed. I read your column every day, and most of the time I agree with you and respect your opinion.

My husband's best friend, "Earl" (not married), has been cornering me alone and keeps saying he has always loved me! I have tried avoiding him, and he tries to avoid me when he's sober. However, we are social drinkers, and since they are such good friends, there are times we can't avoid each other. I have never encouraged Earl and have let him know that I'm very much in love with my husband -- but that doesn't stop him.

Should I tell my husband? I'm afraid if I don't, he'll hear Earl one day and think there's something going on. They have been friends for years, and I'm afraid if I tell, their friendship will be hurt, and I'd never do anything to hurt either one of them.

Your thoughts on this, please. -- IN A BIND IN BATON ROUGE

DEAR IN A BIND: You are much too kindhearted. If the shoe were on the other food, and your best friend began hitting on your husband every time she got a snoot full, wouldn't you want to know?

Corner Earl in the cold, sober light of day and tell him that his unwelcome advances have made you uncomfortable for the last time and if it happens again, you WILL tell your husband. And if you're put on the spot again -- do it.

DEAR ABBY: A friend of ours has a 7-year-old son who molested our 7-year-old child. We alerted our friend to the situation, and she confronted her son, who admitted the act.

From what our child told us, this was not just "curiosity." Our friend took her son to a child psychiatrist and informed us that they discovered the boy had been molested for over a year by an older boy. Then we were told that he would have to be in therapy anywhere from six months to a year.

After two or three visits to the doctor, the mother stopped taking him because it was too upsetting for the child, and he would cry and get sick before the appointment, so no more therapy.

Do you think this is wise? Since he was molested and has acted out on other children (ours was not the only one -- there were several), should he or should he not be in therapy? I believe he should. -- CONCERNED FRIEND

DEAR CONCERNED FRIEND: I, too, believe the boy should be in therapy. Is the boy rebelling because he dislikes the therapy -- or the therapist? Perhaps another therapist could be a solution.

DEAR ABBY: Bravo to you for your recent response to the letter from the Canadian woman whose husband was in prison.

My father went to prison just before I was born. My mother always told me he was "in the Army," since, like your reader, she didn't think I was old enough to understand. Unfortunately, the neighborhood children didn't take my young age into consideration when they informed me that my father was a "jailbird."

Later, my mother apologized for her mistake in not being the one to tell me the truth, even though it wasn't pretty. She never lied to me again about anything, as she expected me to always be truthful with her.

How much better it will be for your Canadian reader's children to hear the truth from someone who can convey it to them in a loving, sensitive manner. They have the added bonus of their father not being guilty of the crime. Unfortunately, I can't say the same about my father. -- EVERGREEN, COLO.

What teens need to know about sex, drugs, AIDS, and getting along with peers and parents is in "What Every Teen Should Know." To order, send a business-sized, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Teen Booklet, P.O. Box 447, Mount Morris, Ill. 61054-0447. (Postage is included.)

DEAR ABBY: For our 33rd wedding anniversary, my husband took me to see "Miss Saigon" at Cincinnati's new Aronoff Center. We had wonderful seats for this spectacular play; however, it was totally ruined by a very inconsiderate 60ish man who was seated directly behind me. He coughed incessantly during the entire performance.

There were times when I felt my hair blowing from the force of his cough! He seemed oblivious to the fact that he was annoying anyone, never bothering to cover his mouth, or take a cough drop, or perhaps get up and leave.

Abby, he was not alone; he had a nicely groomed woman with him who could have at least nudged him or told him to cover his mouth.

When telling my daughter about this, she suggested that from now on I carry cough drops to offer people who do this, thus conveying the message that their coughing is very annoying.

Abby, what's your opinion on handling such a situation? I came very close to saying something, but I didn't want to stoop to his level of rudeness. -- SALLY IN CINCINNATI

DEAR SALLY: No one would deliberately cough under these circumstances, but since this gentleman (?) seated behind you made no effort to cover his mouth and had coughed so violently you felt your hair blowing, you would have been justified in turning around and asking him politely to please cover his mouth when he coughed.

DEAR ABBY: I'm a 42-year-old man who has been divorced for four years. I have a 13-year-old daughter I'll call "Suzie." Since my divorce, it's been Suzie and me and no one else.

About eight months ago I met "Jill" -- a terrific lady with whom I'm very much in love. I never thought two people could have so much in common.

My problem: Whenever Jill and I make plans to go to dinner at a friend's house, Suzie expects to be right there between us. This was fine the first few times, but now it has become a problem. Suzie was supposed to stay with her mother during Easter vacation, but within 36 hours she was standing at my doorstep ready to come home. (She used to love going to her mother's.)

I have sat down with my daughter and told her I love her very much, and she'll always be important to me -- but Jill and I need and want some time to ourselves. It hasn't worked. If I exclude Suzie she cries, calls us names and throws a fit. It has reached the point where we have to sneak around and lie in order to be alone.

How long must we endure this? I plan on spending my life with Jill. So far, she's been very understanding. What should I do? -- SUZIE'S DAD

DEAR DAD: Your problem stems from the extended period when it was you and Suzie and no one else. And you are expecting your child to reason like an adult, while she is fighting for her most precious possession -- her daddy.

You have two choices: Be firm with your daughter and assert yourselves as adults who need time and space for yourselves and refuse to be swayed by the tantrums. Or be prepared to wait until your daughter is ready for college or a life of her own before taking your relationship with Jill to another level.

Abby shares more of her favorite, easy-to-prepare recipes. To order, send a business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, More Favorite Recipes, P.O. Box 447, Mount Morris, Ill. 61054-0447. (Postage is included.)