DEAR MISS MANNERS: If I receive stationery as a gift, is it best to write the thank-you note on that stationery?

GENTLE READER: Etiquette may not, strictly, require it, but it is certainly best, as it avoids any implied criticism that you would have preferred something different.

Miss Manners realizes that not all gifts are given by someone in a charitable frame of mind: Gentle Readers have informed her of stationery being given as a way to signal a dissatisfaction with prior thank-you notes (or the lack thereof). But she also chooses not to look for trouble.

DEAR MISS MANNERS: I work at a coffee shop/cafe that gets very busy during lunch. One day, while I was working the main register with a long line of customers, some kind folks completed their lunch order, paid, then left $10 in cash and asked me to apply it to the order of the man behind them in line.

I figured he was a friend of theirs and didn’t question them further. When the man came to the register, he just asked if he could please have some water; I pointed him to our water station. He went off and I realized he was whom the couple had left money for, presumably charitably.

I couldn’t shout him down, so I tried to attach a note to the bill for a co-worker to take to the couple. However, it was the middle of the lunch rush and I wasn’t able to leave the register.

Later, when things quieted down, the couple came back. I immediately handed them their money, apologized, and started to explain. They told me, somewhat resentfully, that they wanted to give the man money but wanted to spare him the embarrassment of receiving it. They “thought I could explain to him he had credit to use.”

I felt bad about the whole interaction -- I wish the man had gotten to benefit from that $10 -- but also annoyed! It seems like these people were avoiding their own embarrassment, not his, but that it was his loss. I’ve helped plenty of customers buy food for other people, including local homeless folks, and there are many gracious ways to do so. Am I just bitter here, or am I justified?

GENTLE READER: Like etiquette itself, the server-customer relationship depends upon reasonable restraint on both sides. Such restraint includes being clear -- not leaving you to guess what you were being asked to do or how to do it. And it requires staying reasonably close to the task at hand: The service you were advertising was coffee and perhaps a doughnut, not social work.

Your customers failed on both counts. There are, indeed, better ways to accomplish what they wanted, and there are certainly ones that do not put the work on you. Miss Manners wishes that employers exercised equal restraint by not looking at every transaction as an opportunity to sell the next product (except by demonstrating exceptional service).

(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 more mature millennial friends (those of us in our late 20s and early 30s) tend to co-host parties as a group for various celebrations: birthdays, engagements, holidays, etc. Generally, prior to this point in our lives, there was an even split amongst the group for the cost of the event.

However, now that some of us have partnered up, there has been a move to a “couples rate” and a “singles rate” for sharing the costs. For example: $300 for a couple and $175 for singles. But many of our single friends have found the additional cost of hosting the party an unfair “tax” or penalty for not being in a committed relationship.

Is there a difference depending on the event? Say, a holiday party simply for the groups’ common and ancillary friends, versus an engagement party for a sorority sister to whom most of the partners are not close?

GENTLE READER: It has not often been Miss Manners’ experience to hear “mature” and “millennial” used in proximity (unless by way of contrast). But since you have done so, she will answer by saying that the obvious solution is also the mature one: Stop charging admission to gatherings, and let each host throw his or her own party. It will spread out the expense -- roughly -- without endangering longstanding friendships over $25.

DEAR MISS MANNERS: I invited our neighbors and longtime friends to dinner, and asked how many would be attending. They have two college-age children, one of whom lives at home, while the other attends college a few hours away.

While we expected up to four attendees, the reply came back “five.” They had invited their son’s girlfriend to come with them. This is a girlfriend, not a fiancee, nor does she live in their home.

Since when is it permissible to invite others to attend a sit-down dinner at someone else’s home? We do not know this girl! If they want us to meet their son’s girlfriend, shouldn’t it be at a get-together at their home?

GENTLE READER: Sympathetic as Miss Manners is to the plight of the hostess whose guests multiply without invitation, she understands your neighbors’ confusion. You did, after all, ask how many people were coming.

It would have been better to ask after the children -- thereby ascertaining their whereabouts -- and then issue a more specific invitation. Failing that, your neighbor should have volunteered who was around and then asked whom you wished to include. The proper way to avoid the unwanted extra guest is to express pleasure at the thought of meeting her, but apologize that it will have to wait for another occasion. This is more convincing if you have not just moments before issued an open-ended invitation.

(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: You (and others before) have made it clear on how to politely conduct a dinner-table conversation at a party: The rule is to first speak with the person on your left, followed by the person on your right.

But of course, if I speak to “Mr. Left,” and he, too, is speaking with HIS left partner (not me), and so on -- how does this work? Likewise, when I speak to “Miss Right,” she must necessarily ignore me if she is speaking with HER “Miss Right.” I find this does not work very well at all, due to so many swiveling heads, and it’s quite difficult to carry on two different conversations at once!

GENTLE READER: You are quite right. And the thought of everyone whipping around in the same direction, only to be confronted with the backs of heads, is likely to cause not only silence, but whiplash.

The fault, Miss Manners realizes, is in the laudable modern tendency to remove gender as an automatic factor in the interest of fairness. For example, we etiquetteers now instruct people to hold doors open for one another, not just gentlemen for ladies.

But sometimes that is overzealous. In this case, it should have been specified that the traditional rule is that the hostess turns to the person on her right, and the other ladies at the table do the same.

But what (you may ask) if it is a host who is presiding? And if the guests are not distributed around the table in alternating genders? And what if there are other gender factors involved?

You see the problem. So let us restate the rule:

The person giving the dinner turns right, whereupon alternating guests should do the same. Does that help?

DEAR MISS MANNERS: For some reason unknown to me, my daughter-in-law now addresses my son by his surname rather than by his first name. I thought it strange when I heard it for the first time, but did not realize it had become a habit until someone who recently spent time with them commented on it to me.

I think it is disrespectful to my son, but hesitate to say anything to him or to his wife because I do not know if it is my place. I do not want to interfere, but I do want my son addressed with respect. What do you suggest, Miss Manners? Your help is deeply appreciated.

GENTLE READER: It might not be. Nor your help, either, Miss Manners suspects.

How married couples choose to address each other cannot be fathomed by outsiders, even closely related ones. Only they know what is meant to be affectionate and what is not.

Even “darling” may be said in a disrespectful tone. (Miss Manners is thinking of the way the husband in an otherwise happy couple said to his wife, “Sweetie (drawing out the word so that it seemed to have 10 E’s in the middle), that was my king you trumped.”)

So for your own sake, as well as your son’s and daughter-in-law’s, it would be wise to accept the fact that you don’t really know how this was intended.

(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.)