DEAR MISS MANNERS: I need some help on how to cut conversations short gracefully when acquaintances and strangers start going on and on about their intimate medical problems. I don’t want to seem uncaring and do not want to go around hurting others, but I am frankly fed up with self-centered people.

I am not close to these people, but I am about to start cutting them off with something like: “I am sorry to hear of your illness/misfortune, but I really can’t deal with hearing the details. Please rest assured I give you my best wishes, but I really must be going.”

Please give me something more polite!

GENTLE READER: Would you settle for something more effective (but within the bounds of politeness)?

In your most compassionate voice, say, “Please stop. I feel for you -- so much, in fact, that I get squeamish when I hear about illness, and you won’t want to be around me. I’m really sorry, and I hope you understand.” Miss Manners trusts that they will understand that the physical consequences of nattering on would be dire.

DEAR MISS MANNERS: Are there etiquette rules for when restaurants suggest how much to tip? Most restaurants these days are helpfully calculating various tip percentages and printing them on the check.

Typically they calculate 15%, 18% and 20%, but I’ve also seen 25%. In the past, I would calculate 20% and round up or down to a whole number of dollars. If the restaurant is helpfully suggesting 15% as a possible tip, is it rude to only tip that much?

GENTLE READER: Generally, it is not a good idea to take tipping advice from those expecting to be tipped. Often, ridiculous amounts are suggested.

But while 15% is a reasonable tip, Miss Manners hopes this will not discourage you from exercising your customary generosity.

DEAR MISS MANNERS: When I got married a little over a month ago, I did not register for gifts. We were surprised and delighted by some homemade presents and useful objects, some generous donations on our behalf, and some cards and cash.

But about one-third of our guests gave us nothing -- not even a card with well wishes. I was prepared for “no registry” to be read as “no gifts,” but I was surprised that so many attended without even bringing a card.

I’ve heard that wedding guests have a year to give a gift; do we need to wait a year to see if one is given? Or should we send notes thanking them for attending when we send thank-yous for the gifts and cards? I’m worried that will come off as a reminder to pony up a present.

GENTLE READER: Yes, it will, but that seems to be your intention.

When you decided to forgo a registry, Miss Manners fondly believed that you were that rare bride who does not believe her wedding to be an opportunity to shop at other people’s expense. And she was glad that you appreciated receiving thoughtful presents. Please do not spoil this by focusing on getting more loot.

Yes, wedding presents may be given -- or not -- within a year after the ceremony. But hosts do not normally write to thank guests, and there is no point in wedding guests handing over cards.

(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 have noticed a trend in casual customer service workers’ way of speaking. As I’m checking out at the grocery store, the bank or the pizza restaurant, many workers ask, “What are you doing the rest of today?” or “What are you up to today?”

While I’m all for friendly chat, I find this question odd, invasive and a bit rude. I hardly believe that they care about my daily, tedious comings and goings, so really the question is insincere. What is the most kind, polite way to respond?

GENTLE READER: No, they don’t have a sincere interest in your plans, any more than you have in theirs. They were instructed to make conversation with the customers, and may even have been told to ask that exact question.

The idea is supposed to be that it makes the store seem welcoming. But a uniform question does not allow for the fact that not everyone doing errands wants to chat. Some do, sometimes -- and others, never. Miss Manners enjoys this when on vacation (with the fun of speaking a foreign language), but not always at home, when she is more likely to be in a hurry.

Clerks should be allowed to judge whether an individual seems amenable. Sometimes a pleasant “Hello” is all that is required.

But if it would be useful for them to have a standard opening, personal questions from a stranger will not do. We call those nosy. So, by the way, is commenting on the customer’s groceries, as in, “I see you like beer and chocolate.” Or on the withdrawal, as in, “Making a big purchase?”

That is why we have the weather, the traffic and the weekend game to lament. But not the election.

DEAR MISS MANNERS: How do I uninvite guests who are no longer welcome due to their child’s behavior after the guest list was sent out?

I have been polite and direct, telling them that they’re not obligated to come to the event. After several phone calls and text messages, they still ask me, “What do you mean by that?” and “Can you explain what you are stating?”

GENTLE READER: As you were being neither polite nor direct, Miss Manners is not surprised that these people were confused. Or perhaps they just cannot believe that you would do something so rude as to rescind an invitation they have accepted.

How bad where those children? If you really cannot take them one more time, giving only adult parties in the future, you could say, “This is really not a safe environment for the children” -- and indeed it is not, considering how you feel about them -- “but we’re looking forward to seeing the two of you.”

DEAR MISS MANNERS: I know that the fork goes on the left of the plate and the knife on the right. But what if there is no knife? May I put the fork on the right, since I will presumably be using it with my right hand?

GENTLE READER: No. Whatever energy you would save by not having to reach to the left is not worth overturning established eating rituals, confounding your host or waiter, and disappointing Miss Manners.

(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: Many months ago, my husband and I purchased tickets to a popular Broadway musical that was on tour in our city, and we were looking forward to the production. We arrived early and were in our seats before the rest of our row.

A very large man took the seat next to my husband. The seats in this venue are not generously wide, and as he sat down, the man cheerfully said to my husband, “I hope you don’t mind if I am touching you.” Then, before my husband could reply, the man laughed and said, “Well, I guess it doesn’t matter if you mind or not!” My husband just smiled politely.

The man kept one arm on the armrest he shared with my husband and the other arm on the armrest he shared with his wife. Throughout the first act, he talked to his wife. It was so disruptive and physically uncomfortable that my husband and I left at intermission.

What, if anything, would have been the proper response to this man? I am empathetic that the seat must have been uncomfortable for him as well. But it seemed impolite that he should laugh that his problem now became my husband’s.

GENTLE READER: Etiquette addresses behavior, not states of being. Miss Manners is afraid that this man’s attempt to make light of his inability to change his size -- after a lifetime of people rudely suggesting otherwise -- was his idea of a pleasantry. By leaving after intermission -- while your prerogative -- you likely reinforced that thinking.

The main infraction here was his incessant talking during the performance. If a tap and a look didn’t work during the show, at least some of your comfort could have been remedied and addressed during the intermission by your saying, “I wonder if you wouldn’t mind limiting your conversation during the performance. We had trouble hearing.”

DEAR MISS MANNERS: A friend and his wife invited me out to dinner last night with another lady. When the lady seated next to me rose two or three times during the meal, I stood up, as I was taught, but my host did not.

Was I right to do this? It is not my place to teach other people etiquette, and I also did not want to embarrass my host or put him ill at ease. Perhaps I should do this only when I am the host.

GENTLE READER: While manners dictate that one does not directly point out the lapses of others, they certainly never discourage leading through example. You are perfectly correct to stand when a lady leaves the table -- and since you are her dinner partner, it is reasonable to have that duty fall to you rather than the host of the evening.

Miss Manners will only add the caveat that if the lady is leaving two or three times during dinner, your frequent bobbing up and down, while technically correct, may start to feel excessive -- and draw undue attention to your partner’s continual need to be somewhere else.

(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.)