DEAR MISS MANNERS: A friend of mine told me that her 19-year-old daughter had received a gift (on no special occasion) of a Tiffany necklace and pendant from a man she had been dating for two months.

My immediate reaction is that my mother would have made me return such a gift as inappropriate. My friend doesn’t see this as a problem, and I can’t find anyone else who understands my mother’s rule on the subject. Is it outdated now?

GENTLE READER: Speaking of outdated -- is it possible, in the light of recent public revelations, that the mother of a teenager believes that there are no strings attached to such a present?

Of course, she should have known anyway. But Miss Manners presumes that the “outdating” that you suggest refers to the naive belief that all relations between the genders should be carefree, and that power -- in this case in the form of money -- is not a factor. Surely that has been dispelled.

DEAR MISS MANNERS: We are invited to a formal wedding. It will be a fun evening. I was thinking of wearing a white dinner jacket. My wife says “no,” and that I should stick with black and not stand out.

She’s probably right, but I still think it would be fun to wear white. What do you think of white dinner jackets, in general?

GENTLE READER: That they are fine for waiters and band members with summer engagements. And that “fun” is not a proper guideline for a gentleman’s appearance.

DEAR MISS MANNERS: Is it rude to not return a “hi” to a co-worker who has abused you terribly?

GENTLE READER: Technically, the “cut direct,” as this is known, is recognized within the manners realm as an extreme weapon. It means that the person is not recognized as being in the world of civilized behavior. If Hitler tries to shake hands with you, you turn your back and walk away.

You should know that a lesser weapon is possible, which is to respond coldly and curtly. This would seem better in regard to people with whom you still have to work. But as you have not told Miss Manners the nature of the abuse you suffered, she does not know if the nuclear weapon is justified.

DEAR MISS MANNERS: I enjoy cooking and entertaining, and have always honored guests’ dietary restrictions at my table as they are brought to my attention (vegetarian, vegan, food allergies, etc.). Recently, I have been asked in both personal and professional settings to provide special foods for guests’ weight-loss regimens. Is this reasonable?

GENTLE READER: If you are prepared to cook individually tailored meals for everyone who asks, you should be in the restaurant business.

It is not that Miss Manners believes that one shouldn’t make a reasonable effort to accommodate one’s guests. Nowadays, it is advisable to ask in advance if they have any food restrictions and to vary the dishes so that no one goes hungry.

But guests also have a responsibility to be accommodating. If their restrictions are such that they cannot manage a meal unless it is specifically tailored to their requirements, they should eat beforehand and attend for the sociability.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: My husband works at an institution where there is a chancellor and a president. What is the correct title to use for the wife of the president?

I would have thought “first lady,” but isn’t that how you would address the wife of the chancellor?

GENTLE READER: Even the wife of the president of the United States has no official title, no matter how often she is referred to as first lady. That is something that President Kennedy’s wife tried in vain to avoid, pointing out that “First Lady” sounded like the name of a horse.

And with the ersatz title, expectations have arisen about what duties a first lady -- of whatever job her husband holds -- should perform, regardless of her inclinations, skills or other priorities. That many generously comply should not make it compulsory for all.

Miss Manners urges you to drop and discourage the notion of such wifely titles. If the wife of your chancellor or president is a professor or a doctor, use that title in addressing her. Otherwise, the correct protocol at all levels is to address her as “Mrs.” or “Ms.” with her surname.

DEAR MISS MANNERS: We were invited to a “bridal couples’ shower” as friends of the groom’s parents. I take pride in trying to find the perfect gift.

After we arrived, the mother of the groom asked us if we would mind if the gifts weren’t opened during the shower. She said the couple was “too shy to open gifts in front of everyone.” She added that we would receive a very nice thank-you card.

I was surprised and disappointed, as I would have liked to see them open our gift. Is this the norm for our upcoming newlywed generation?

GENTLE READER: On the contrary -- these young people grew up with the ritual of children opening birthday presents in front of their guests, and many have concluded that it should be abandoned.

It depends too much on the young host’s being able to express gratitude, even if disappointed and in case of duplicates, and on the guests’ being able to suppress envy. In addition, it sets up an implied rivalry among the guests.

So while these are behavioral lessons to be learned, Miss Manners approves of using the occasion instead to teach how to entertain and be guests and to write letters of thanks.

That your grown-up friends are skipping this questionable ritual seems sensible to Miss Manners. It should not have been necessary for the mother to explain that appreciation of your present would be expressed in a letter.

DEAR MISS MANNERS: My friend, her husband, my husband and myself ordered carryout dinners from a restaurant where my friend’s husband does free plumbing work, and the restaurant, in turn, will give him free platters.

I offered to pay for my husband’s and my part of the order, and my friend said no. I felt bad, so I insisted she take it, but again was told no. If my friends were not charged for the carryout, should I be obligated to pay?

GENTLE READER: You are obligated, but not to pay. It disturbs Miss Manners that so many people believe that money is the only way to pay social obligations. Your friends have entertained you, and the way to reciprocate is by inviting them.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: After a fishing trip, we invited over some friends who live about an hour away to enjoy our catch. They replied that they’d love to, and reminded us they have two dogs now.

Before we replied, they wrote again: “We hope you can put up with us and our two weird dogs for the day, and overnight if we drink too much.”

When they had just one dog, we invited them in the summer when we spent the day outside. I stated the invitation was meant only for them and we were not prepared to include two dogs at this time -- considering it will be rainy, my husband is allergic and our home was recently remodeled, including new hardwood floors. These are not lap dogs, more medium-sized (40 pounds).

They were then unable to come and were sad to hear we didn’t welcome their “well-behaved girls.” They said their house was open if we wanted to come there. Any better way I should have handled this?

GENTLE READER: ”I’m afraid that our house is ill-equipped for your dogs, but we would love to have just the two of you” is likely what you thought you said.

But anyone reading your letter, including Miss Manners, clearly inferred that your hardwood floors were more important to you than their dogs.

This is clearly not what they wanted to hear. Since your friends seemed to have remained in good standing by asking you to come to their house instead, however, Miss Manners advises you to take them up on their offer graciously.

DEAR MISS MANNERS: I do coursework on the weekends at the public library in my town. They have several sets of large and small tables.

Because I need to spread out lots of papers, books, notepads and my laptop, I sit at a large four-person table, which also has a built-in electrical plug for my laptop. These tables have hard wooden chairs with high backs. The smaller two-person tables have no plugs, but wider seats with padded cushions and low backs.

I have disc degeneration and a herniated disc, so sitting still for long periods of time and not being able to stretch take a toll on my back for the four to six hours I am at the library. I have started to swap out the chairs, always putting them back. For what it is worth, tables are not at a premium and there are plenty to go around.

I now feel guilty not only for being a single person at a large table for four, but for also swapping the seats. This hasn’t inconvenienced anyone as far as I can tell, and I do have a genuine disability, but I feel I may be rude to take up so much space and swap chairs to make myself comfortable, even if no one has complained.

GENTLE READER: As with public transportation and any other unreserved, unpaid seating, the solution is to offer to move if someone asks. Miss Manners suggests that you do not invite complaint when none is being issued.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)