DEAR MISS MANNERS: When, if ever, is it appropriate to use “reply all” in group emails? Only when asked to? I find it annoying when people reply to all.

GENTLE READER: The proper time to reply to everyone is when the answer can reasonably be expected to be of interest to the group -- and when your response respects the context, tone and subject of the original.

A company email from the boss explaining a new policy is not an invitation to tell everyone you object. A serious email about the water being shut down in the building is not an invitation to make a joke about the cleanliness of said water. And an email from your cousin announcing the date for the family reunion is not an invitation to open a debate about who is hosting Easter.

DEAR MISS MANNERS: My brother’s wife absolutely hates his ex-girlfriend, and verbally states so at every given opportunity. She does so using vulgar terms, regardless of who is around -- my children, my parents, other family members, complete strangers.

This now-married couple began their relationship while they were both in other live-in relationships. They would lie to their partners about where they were and who they were with. My brother kept it secret from our family for years while they cheated together, and when it all came out, there were messy breakups. The two of them have now been married about two years. They have a lot of trust issues with one another, and they do not have a peaceful marriage.

We all got along very well with my brother’s ex-girlfriend, and I still value her friendship. My brother’s wife told me to tell my mom that if we do “anything nice” for the ex-girlfriend that it would be showing her disrespect, and that she is “putting us on notice.”

The ex-girlfriend, who is now happily married and expecting her first child, remains a dear friend. She is kind and loving, and has done no wrong in all of this. My brother has often asked me what I think of his wife, and Miss Manners, I am at a loss as to how to respond. I have told him, “I don’t know her well enough to answer that yet.”

How do I shut down the ultimatums and let my brother’s wife know that I do not wish to fight with her? How do I politely tell my brother what I think without hurting him or pushing him away? He is asking what I think of her so often that I don’t think he believes my line anymore.

GENTLE READER: Although she does not know your brother, Miss Manners agrees that he does not believe your feelings for your sister-in-law are neutral. This is not a problem, but an opportunity, as your sister-in-law is clearly not someone with whom you can have a civil conversation about the ex-girlfriend.

The answer to your brother is that you really want to love your sister-in-law as you know he does, “but her ultimatums about the ex make it a challenge.” This may be more subtle than the quid pro quos to which your brother has become accustomed, but for that reason, it is less likely to damage your relationship with him.

(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: I enjoy picking out “just the right gift” for various family members at Christmas. However, each year, several family members ask me what gift they should purchase for my children. My mother insists that I am being difficult for not providing her with a gift list.

I find these requests incredibly tacky. Am I being unreasonable for being unnerved by this practice and not participating?

GENTLE READER: Although Miss Manners believes that the meaning behind giving presents is the thought put into their selection, she is not dogmatic on the point. Being unnerved by your mother’s request for help, or calling it tacky, is too emphatic for holiday cheer.

It has been some time since your mother had a 10-year-old. Treat her request as a genuine desire for guidance on what would be meaningful, which requires providing something more than a rebuke and something less than a list of catalog numbers.

DEAR MISS MANNERS: In a recent delivery of my daily newspaper, there was a letter in rhyme from our paper deliverer, touting her services throughout the year. I received the same “poem” from our previous carrier, and most years, I sent a holiday gift (monetary) in the mail. This new carrier, however, also included a self-addressed envelope to accompany her letter.

While I am generous by nature, this was a turn-off. There’s a part of me that would like to respond in writing that I normally send a check to the carrier, but because she included an envelope, I was offended. Or should I give up, succumb to the convenience of not needing to address an envelope and simply write the check?

GENTLE READER: Do you wish to be the customer in apartment 2B who expressed gratitude for a year of service, or the grouch who (rudely) corrected another person’s manners? If, after you have chosen the former, your carrier neglects to send a thank-you letter, in rhyme or not, then next year you have Miss Manners’ permission to skip the holiday gratuity -- without an accompanying etiquette lesson or other explanation.

DEAR MISS MANNERS: Here come the holidays, and with them come gifts shipped from various online retailers. Last year, a gift arrived with no indication of who sent it! How can one learn whom to thank? Casually working the conversation around to the topic of anonymous gifts arriving in the mail is burdensome, but possible. Unfortunately, the “suspect” I had in mind for last year’s mystery gift was a person I see only rarely, so that didn’t work out. This year, I want to be prepared with a strategy that (I hope!) you will supply.

GENTLE READER: In these days of online shopping, matching unmarked presents with their givers appears likely to become a permanent feature of the holidays. While Miss Manners recognizes this is less welcome than the gifts themselves, she takes consolation in the likelihood that the number of suspects is limited. It is therefore not unreasonable to expect a limited effort to identify the perpetrators.

Calling someone you have fallen out of touch with does not seem like a major imposition and may, in fact, add to your -- and their -- holiday cheer.

(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: When my friend’s computer was broken, she asked if she could come to my house to attend an online meeting that I, too, was attending. I said yes, and jokingly said that I believed the rule is that if you leave the house to attend an online meeting, you must wear pants. She wrote back, “Under- or outer-?”

I was loath to commit to an answer. I know that there are instances when these categories blur.

Can you explain the manner of dressing that might be expected of a guest who has come over specifically to attend an online event where attendees will be seated, and whether the online event or the visit should guide the host’s attire?

GENTLE READER: The simple answer is to dress for the meeting, as the host is merely providing an entrance to that. But also not to violate decency laws by leaving home without pants.

However, Miss Manners considers the real problem here to be that it is time to retire that joke about not wearing pants when their absence will not be visible. You tried it, and your friend tried to make a joking reply, but neither went over. We are all very tired of it.

DEAR MISS MANNERS: I’ve never been part of a cache of friends and couples who have methodically gone through the marriage and parenthood thing. But where did the “gender reveal” ritual come from? And why does it exist, except to net gifts? Why do expectant parents believe it is so important to announce the sex of their baby? It used to be they were just happy to birth a healthy child.

In a typically American way, gender reveals have gotten grandiose and out of hand. One gender reveal party used a smoke machine for effect, which started a fire in California that burned tens of thousands of acres.

Why do these couples believe they are the first to ever birth babies? If anyone’s listening, Miss Manners, you should say, “Don’t be so stupid!”

You expect a lot from people. I can imagine your disappointment.

GENTLE READER: Thank you; Miss Manners would like to take a moment to weep on your sympathetic shoulder.

She would be all for inventing new ways to entertain friends, if only they weren’t all connected with the expectation of raking in presents.

DEAR MISS MANNERS: I work in a pretty large building, where we are all working toward the same goal. We pass each other in the halls many times a day. Is it rude to NOT say hello (or a similar greeting) every time we see each other? I’m thinking the first time we encounter one another should be sufficient. What say you?

GENTLE READER: Ordinarily, a smile would be enough for subsequent encounters. But as Miss Manners presumes you are wearing a mask, a quick hand wave should do it.

(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.)