DEAR MISS MANNERS: Long ago, I was trained that when someone says “thank you,” you say “you’re welcome” (unless, of course, they aren’t). This has always worked well for me in person and on the telephone.

Now, however, the modern means of communication ensure that I almost never actually hear a co-worker’s voice. Still, when someone emails me a thank-you, I respond with a “You’re welcome!”

I have recently noticed (yes, I’m slow, always was) that no one else does this. So now I wonder if modern etiquette means that not only is my response superfluous, but even perhaps annoying. After all, the only thing to do with an email like that is to delete it.

Not that I’ve received any complaints, but should I stop doing this?

GENTLE READER: Far be it from Miss Manners to discourage conventional courtesies, even superfluous ones. But that is what she is about to do.

Written thanks do not require that acknowledgment. A letter of thanks needs no response unless it is accompanied by a present. (Then it still doesn’t require “you’re welcome,” but does require another letter of thanks for the present -- which the recipient needn’t answer, so that is the end of the chain. Whew.)

Anyway, people’s inboxes are choked with emails, so it would be a good idea to drop this well-meant but unnecessary addition.

DEAR MISS MANNERS: Frequently nowadays, people answer their cellular phones, an entirely voluntary action, by stating, “This is X. What is it? I am busy,” or “I can’t talk now. What’s up?” Today, someone said, “I am standing in my linen closet folding sheets. I don’t have time to talk. What is it?”

Can you recommend either 1. a soothing or satisfying internal thought for the caller, who is thinking, “But I did not force you to answer; why must you be so rude?” or 2. an appropriate reply?

GENTLE READER: For the second, Miss Manners suggests, “Oh, sorry, never mind. Goodbye.” This should leave the rude person forever wondering what was up -- which, in turn, should provide the satisfaction requested in the first.

DEAR MISS MANNERS: I frequently see people going about their business whose masks have slipped below the nose. It’s maybe because it’s too loose, or it sometimes happens when people have been talking.

Should I say something? I know you are against people running around correcting others, especially strangers. And I don’t want to get into one of those explosive confrontations between people who are for or against wearing masks. These people are wearing masks, it’s just that they’re not wearing them effectively.

GENTLE READER: Calling attention to an accidental error that is easily fixable is indeed different from challenging deliberate defiance. It is a favor, rather than a criticism. But it must be done discreetly.

An obsolete example that comes to Miss Manners’ mind is the way one lady might whisper to another, “Excuse me, but your slip is showing.”

No doubt this requires some explanation. A “slip” is now understood to be a small accident, and Miss Manners doesn’t want to shock anyone by saying that it used to be ladies’ regulation underwear. What is now known as a slip dress was actually worn under a real dress. This was back before revealing one’s underwear was considered intriguing, so the slip was supposed to be entirely concealed.

But accidents happen. And they happened so often that a euphemistic reference, “It’s snowing down south,” would be understood.

Miss Manners has wandered into this quaint tangent in search of a quick hint that can be quietly conveyed to someone whose mask has slipped. She supposes that “Excuse me, your nose is showing” will not do. Nor can she think of a cute geographical reference.

So a quiet “Excuse me, I believe your mask has slipped,” accompanied by a sympathetic smile, will have to do.

DEAR MISS MANNERS: Currently, I am in my master’s program, and in a state of intense work within my field. I am also a mother of three and run a nonprofit organization. I’m a busy lady with not a lot of time for B.S.

My friends and family know I am busy, that I am trying to focus, and how important this is to me. These “friends and family” are not only unsupportive, but also contacting me about really arbitrary, useless things.

I just want them to leave me alone for the next few months until my qualifying review. I’ll deal with the “unsupportive” part later. How do I nicely tell people to leave me alone?

GENTLE READER: It’s a good thing that you added the word “nicely.” You sound exasperated, and in danger of saying something that will keep them away when you want them to congratulate you on getting that degree.

If these family members are your minor children, Miss Manners can only offer you sympathy, and she hopes that you find a way to keep them safely occupied. But if they are not members of your household, you should sound apologetic when you tell them that for the next whatever-amount-of-time, you can’t focus with distractions. You are therefore turning off the telephone and not attending to texts, emails or doorbells, but will be happy and relieved when you are again free to have the pleasure of seeing 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: Our very cute dog, “Wally,” has enjoyed the occasional table scrap on top of her usual dog food dinners. As a result, she has added a few pounds to her otherwise sleek physique. Lately, my wife has been gently chastising her, even calling her “pudgy.”

I’m concerned that this is not only a breach of etiquette, but could have a long-term impact on her self-esteem. My wife says that since she’s a dog, it’s of no matter. I say fat-shaming is what it is, regardless of species. We have agreed to let you be the ultimate arbiter.

GENTLE READER: We seem to be scraping the bottom of the pandemic barrel for arguments, are we not?

But yes, Miss Manners agrees with you: Babies and animals should not be subjected to any sort of shaming. Not just because they are unable to defend themselves, but because it sets an unpleasant precedent for their more cognitive counterparts.

Miss Manners suggests that you respond to your wife by saying, “Now, dear, Wally looks as good as any of us after nine months of our delicious cooking.”

DEAR MISS MANNERS: I recently needed to contact my neighbors regarding an issue with our building. I know all of them by name, and have their telephone numbers, except one couple. We do greet each other when we meet in the lobby or the elevators, but I didn’t have their contact information.

So last Saturday around 10 a.m., when I figured most people would be up and about, I went upstairs to their floor and rang the doorbell. I waited for what seemed like a long enough time, and then rang the doorbell a second time. I waited a little bit longer, then, figuring no one was home, decided to leave.

As soon as I entered the lift, I heard their door open, and immediately popped out again to talk to them. The gentleman opened the door wide, but was still in his pajamas. The lady was nowhere to be seen, and there were signs of ongoing housecleaning (a vacuum cleaner in the middle of the floor, etc.).

I apologized. He didn’t invite me in. I explained why I needed to talk with them, we discussed the issue, exchanged phone numbers, and I left.

Should I not have rung the doorbell twice? How long does one wait after knocking/ringing before assuming no one is home? Was 10 a.m. on a Saturday too early?

How would Miss Manners have handled this situation?

GENTLE READER: As a general rule, two knocks and after 10 a.m. work fine. Both of you came out unscathed. Or you could have left a note under the door.

For true neighbor emergencies, however, the timing and intensity will likely be dictated by the situation’s urgency. Basement flooding has precedence, Miss Manners assures you, over sugarless cakes.

(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.)