DEAR MISS MANNERS: The customer ahead of me still had groceries to be rung up, so I waited until her order was clear before placing my items on the conveyor belt. When the cashier began ringing up my items, a woman behind me began pushing my cart against me in order to get her items on every last inch of the conveyor belt. Finally, I said two things to her: “Stop pushing this cart against me. You’re old enough to know basic courtesy.”

She didn’t reply, but the assault stopped. In the same situation, how would Miss Manners have reacted?

GENTLE READER: Your success does not deter Miss Manners from deploring the way you achieved it. If she were not terminally polite, she would say to you, “Stop pushing people around. You’re (presumably) old enough to know basic courtesy.”

But she would never do so. Responding with rudeness only doubles the amount of rudeness being practiced. Also, it rarely works, which is why Miss Manners is surprised that you were not then rammed by the cart. It shows that your attacker had a sense of decorum, and suggests that her offense was inadvertent.

At any rate, you should have treated it as such. “Excuse me, but your cart is pushing me,” would have allowed even a deliberately rude person to retreat without further rudeness.

DEAR MISS MANNERS: I had a destination wedding back in November. We received various gifts from people who were invited (some who came and some who did not), and promptly sent out our thank-yous for that. Just last weekend, my in-laws threw us a “congratulations on your wedding” party with family and friends from the area, some of whom already sent us gifts for our wedding.

Should I send thank-yous to everyone who attended the party, even the ones who didn’t bring a gift because they previously sent us one for the wedding itself?

GENTLE READER: The novelty of being able to tell a bride that she should write fewer letters of thanks has Miss Manners feeling giddy.

She is as sick of nagging derelict brides as are their mothers. (Don’t bother alerting her that she should have written “brides and bridegrooms, as are their parents.” Bridegrooms indeed share the responsibility, but unfortunately, this seems still to be rare, and fathers’ involvement is practically unheard of, possibly because the un-thanked tend to blame the mother.)

Hosts do not need to thank their guests; a cheery “We’re delighted that you came” at the door is quite sufficient. And because many people know this, letters of thanks for attendance tend to be unpleasantly interpreted as meaning that something more was expected.

DEAR MISS MANNERS: When I am invited to a party at which a product is being sold, should I attend even if I know that I do not need any of the products? If I attend, am I obligated to purchase a product?

GENTLE READER: As this is a mixed social and commercial event -- sort of like a program with advertisements -- you have your choice. You can treat it as social, and ignore the commercial aspect, or you can treat it as commercial, and only buy if you really want to -- as you would in a store. In neither case does this require making a purchase.

(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 been dating a woman for about two weeks. We have been together and like each other quite a bit.

We planned a dinner one day in advance for a Tuesday evening. Nice dinner and wine. She sends a text at noon canceling dinner since her friend, who visits from out of town frequently and was already here, decided they needed more time together.

Do I brush it off, reconsider our friendship or move on to better manners? P.S. We’re in our 50s.

GENTLE READER: While kind of you to provide the details of your age, being inconsiderate does not necessarily improve with it.

Miss Manners assumes that you were using it to imply that your friend should have known better. But you could also use your own earned wisdom and patience to give her the benefit of the doubt. Perhaps there was something pressing with her friend.

In any case, it is clearly up to you and the depths of your feelings to see if you want to give it another chance. If you do and she cancels again, you then have unabashed permission to politely move on, with or without an explanation.

DEAR MISS MANNERS: Since I was a child, my parents always taught me that tipping well is very important. If you have the money to go to a meal, then you have the money to leave a tip for those serving you.

I have taken this to heart in my adult life, but have found that not all of my friends feel the same. While I consider 20 percent tip to be the norm in the U.S., maybe 18 percent if things weren’t great, I would never dream of doing only 15 percent.

However, I have more than one friend who leaves that amount, leaving me to overcompensate on my own tab so that the waitress/waiter does not get shorted.

I have stopped accepting meal invitations with these friends because it makes me uncomfortable to be associated with them in that way, and it also drives my bill up even more.

Is there a polite way to bring this up with friends? I don’t want to cause unnecessary conflict, but I do want to find a way to say that what they’re doing is not, in my opinion, right.

GENTLE READER: Pick a time far away from the appearance of the check (at the beginning of a meal, for example, or at a social excursion that doesn’t involve a restaurant), to bring up the subject of tipping, doing your best to disguise it as general conversation. This way you can at least figure out which friends believe that the tipping rate should be lower and which are just genuinely unaware.

You may then skillfully impart your own opinion, perhaps with a few examples from yours or another’s service industry experience. Miss Manners is always in favor of assuming the best of those who may be ignorant as to what is expected -- or haven’t kept up with inflation. Assuming so here may alleviate the problem and potentially save the friendship.

(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: A friend of mine is marrying a cad who is only after her money. Do I attend the wedding to support her, or stay away?

GENTLE READER: Whatever you think of the future Mr. Friend, you have presumably had your say and been overruled -- by the person who will bear the consequences if you, and not she, turn out to be correct.

If the support you intend to offer is of the “You’re going to regret this” variety, Miss Manners suggests you find an unrelated reason for not being able to attend. But as your friend would like you to be there, the preferred course of action is to do so, graciously.

DEAR MISS MANNERS: After serving my company as a manager in an exemplary fashion (as I was frequently told) for over 10 years, I was in line for a promotion, which my boss and all my colleagues knew I wanted and expected to receive.

Instead, my boss chose someone else, and offered me what he considered an even better promotion, except that the responsibilities of that job did not appeal to me at all. So I turned it down. I was only vaguely aware that this “better” position existed; at no time, either when I interviewed for the job I wanted, or before or after this period, did my boss even ask me if I had any interest in this “better” position.

I have accepted that it was his decision to choose someone else, and I still would have turned down the “better” job even if he had handled it diplomatically, but I am very, very hurt by his poor communication.

I still have to work with him, although I won’t be seeing him as often now. I don’t want to be childish about this, I don’t want to carry a grudge, but I don’t like or trust this man particularly anymore. How do I respond when I see him, when he asks me (jauntily, as is his style) how I am doing?

GENTLE READER: It has come to Miss Manners’ attention that modern businesspeople blame everything from rude emails to embezzlement on “poor communication.” She innocently thought the term referred to her cellular telephone’s carefree disdain for clarity and intelligibility.

Your boss committed three actions to which you object, none primarily a failure of communication. He didn’t give you the job you wanted. He offered you a job you didn’t want -- or more precisely, he made a decision for you about what you would like. And he is jaunty, which Miss Manners interprets to mean “friendly, in a possibly condescending and likely unprofessional manner.”

The first is, as you recognize, within his right. The latter two show a poor understanding of the divide between business and personal manners. Do not fall into his error. You have reason not to like or trust this man, but you are not required to do either. He is your boss, not your friend or your father. Treat him with every professional courtesy, and keep your personal feelings for your friends and family.

(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.)