DEAR MISS MANNERS: Somehow I missed the memo that desserts in restaurants are a communal affair.

We are able to go out to dinner only on special occasions, and I limit my alcohol intake to be able to afford dessert. If I order soup, it will always come with one spoon, but the waitstaff almost always decides for me that my small, expensive dessert should come with a spoon for each person at the table.

I have had people take three or four bites while telling us about their co-workers who came in today with the start of a flu bug.

I am tempted to make a pre-emptive strike and tell the server that if he brings everyone a spoon, fine, just bring two desserts and I'll take the second one off the tip, but I know this is not only rude, but also allows for who-knows-what to happen to the food before it is served. Do you have any suggestions for me?

GENTLE READER: Yes: Stop threatening the waitstaff, and not just because you suspect them capable of nasty reprisals. Although Miss Manners shares your dislike of the automatic assumption of sharing, a great many people do ask for extra spoons, and it is not a high crime to hope to save a trip.

However, she will protect you from sharing your goodie. Just make your pre-emptive strike a bit less harsh. You could say good-naturedly to the server, "Thank you, but I'm sure this is so good that I'll want to devour it all," and to your companions, "Does anyone else want to order one?"

DEAR MISS MANNERS: When I visited a museum with my mother, we noticed other visitors taking photos of the exhibits with their cellphones. My mother and I were taught never to take photos in a museum, that it deprived the museum of its "product," as it were, and could damage antiquities.

Is this no longer the case? The docents and guards did not correct the photographers, and no signs were posted prohibiting photography.

GENTLE READER: Ordinarily it scares Miss Manners to be asked if a rule is no longer in effect. What follows is usually the declaration that an act of basic decency, such as answering invitations or giving thanks for presents, is so frequently violated that people honestly think it must have been repealed.

So it is with relief that she is able to tell you that indeed, the rule against taking photographs in museums has changed. Those institutions that keep the ban, in order to retain control over reproductions or to respect that policy in regard to exhibitions on loan, will post signs.

But it is no longer the default rule, now that the danger of exploding flashbulbs has passed, with the development of fast, electronic cameras, including those in telephones.

However, the rule against confronting strangers is still in effect. Miss Manners does not want to discourage you from reporting overly enthusiastic museum-goers who may be cutting a painting from its frame or chipping a souvenir from an artifact, but such violations should be reported to a museum guard.

(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, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: If a lady is being presented to the president of the United States and his wife in a formal setting, what rules must be followed in order not to offend, or attract the attention of the Secret Service?

Should she extend a hand to the president, or wait until he does so? Is it permissible to look him full in the face, or should she cast her eyes down demurely while murmuring a polite greeting? Are the rules the same for his wife?

And speaking of greeting, one's assumption would be that "Good evening, Mr. President" would be acceptable for him, but how does one address his wife? Mrs./Madam President? Mrs. First Lady? Mrs. Obama? (My assumption is that "Hey Michelle" would not be a good idea.)

I want to make my country, and Miss Manners, proud.

GENTLE READER: A worthy thought, for which Miss Manners thanks you. She presumes that you also take pride in being the citizen of a country that distinguishes respect from obsequiousness and allows us to look our leaders full in the face.

After some debate, our Founding Fathers ruled that court etiquette, with its flowery titles and knee-bending to superiors, was not fitting for a dignified republic. Therefore, our highest official is not His Extraordinarily Important Worship, but, as you note, simply "Mr. President."

His wife, although popularly known as the First Lady, is legally a private citizen with no official title to go with what have come to be enormous responsibilities. The only concession is that she is THE Mrs. Obama, as opposed to any other lady who might happen to have that surname, so should be addressed in writing, as well as face-to-face, without using a given name. Woodrow Wilson's wife had two sets of cards: "Mrs. Woodrow Wilson" after he left office, but just "Mrs. Wilson" during his presidency.

And don't worry about the handshake. Royal subjects are forbidden to initiate any form of touch with their sovereigns, but Americans find that their leaders, being politicians, are only too eager to shake hands. He will probably have his out faster than yours.

DEAR MISS MANNERS: I am a lady who must use a cane when walking due to a medical issue. Many times at social or other gatherings, well-meaning friends will walk alongside me to "assist" me.

This kind gesture often leads them to accidentally and unknowingly kick my cane, which sends me reeling. My friends usually exclaim, "You MUST be more careful!"

I do not wish to be rude, but how do I let them know that they are the ones who must be more careful?

GENTLE READER: This is a version of the scout who kindly helps someone across a street she didn't want to cross. It is unfortunate that the tender-hearted are often tender-headed enough to think that they know more about the logistics of handling a disability than those who have one.

Miss Manners hears of such would-be helpers taking command of wheelchairs to the annoyance and possible endangerment of their owners. Intended as an act of kindness, that is actually an act of arrogance. And your friends are compounding their error by scolding you.

You will have to assert your authority by saying firmly, "Thank you, I can manage," or, "Please walk on the other side."

(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, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: Was it tacky of me to throw my own birthday party?

I wanted to use my birthday as an excuse to have a fun party, so I invited friends, who all agreed in advance to share the cost of pizza, and I provided cake and cookies. (A plain cake -- I did not write "Happy Birthday, Me!" on it, which I do think would have been tacky.)

Some friends remarked that they thought it was strange for me to "celebrate myself" in this way -- getting my own cake, etc. But these friends certainly weren't about to throw a party for me -- nor did I expect them to -- and this seemed like the best way to throw the party that I wanted for myself.

Is there established etiquette for throwing a party for oneself, and did I breach it?

GENTLE READER: Children give their own birthday parties, with the help of their parents, in the hope that it will teach them how to be gracious hosts.

But many of them must have flunked, because the adult birthday party, in which the host's interest is in honoring himself, often at the expense of the so-called guests, has become common.

Do not expect Miss Manners to reassure you that this is a charming thing to do. As you heard, your own friends were not charmed, although it was unkind of them to say so.

It was, as you put it, "the party that I wanted for myself." Where were your thoughts for your guests -- other than that they should pay for the pizza? How can they help noticing that you are prodding them to honor you?

It is not that mean old Miss Manners expects you to spend your birthday sulking along. But there is a subtle -- and nevertheless crucial -- difference between wanting to celebrate with your friends, and instructing your friends to celebrate you.

By all means, throw a party, if that is what you wish, but then behave like a host. That means planning it for the enjoyment of the guests, not just the fulfillment of your own preferences. It also means paying for the refreshments.

A particularly gracious touch would be refraining from calling it a birthday party, so that guests do not feel obliged to bring presents. But perhaps that is too much to expect, on top of your having to pay for the pizza.

DEAR MISS MANNERS: Is it appropriate to give a widower my phone number? His wife died three months ago after being terminally ill for several years. We are in our 60s and belong to the same club, but rarely have the opportunity to talk.

I would like to get to know him better, and if things go well, spend some time together when appropriate.

GENTLE READER: You and all the other single ladies he knows, some of whom are probably ahead of you in line. You may be sure that he and his friends would snicker about this tasteless and unsubtle way of saying, "Now that she's finally gone, what about me?"

Miss Manners suggests that instead, you try to make friends with this gentleman in the normal way. When you see him at your club, start a conversation. If it or you seems to interest him, you are both free to suggest continuing it later.

(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, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)