DEAR MISS MANNERS: When visiting a bank to be seen by a teller, at what point are you officially in line?

I entered a bank to cash a check, and as I did not need any paperwork, I passed the kiosk where two women were filling out forms, and promptly stood in the line. A few moments later, the women joined me. One began to loudly complain to the other that I had "cut" in front of them.

I listened and then told her that I hadn't and that she was not ready. You can't actively wait in line if you are still getting everything in order.

We had a few more words and before it became heated, I left my spot and walked to the very back of the line, which now had five more people who had entered. The whole experience left a bad taste in my mouth. Was I a line-cutter?

GENTLE READER: Sometimes a line is a social convention: When multiple lines jump over an aisle and then feed into a single point, both the continuity of the line and the need for alternation are implied. But usually, a line is just a line.

Miss Manners has not, herself, perfected the technique of standing in line, balancing a form on her left hand while writing with her right and shuffling forward with her feet. But she has seen it done.

The people filling out forms elsewhere were not in line, and therefore you did not cut in front of them. But you were prudent to cut out.

DEAR MISS MANNERS: I've never experienced a situation where income would dictate the proper manners, but this may be the case.

The CEO's wife of the company I work for gave me a Mason jar filled with homemade granola, and a cleaning person where I work gave me a Mason jar filled with homemade trail mix. I wrote them thank-you cards and I struggled to tamp down my thanks, as both were really good and I didn't want to seem like I was "fishing" for more.

Anyway, the CEO and his wife are worth around $100 million and the cleaning person makes slightly above minimum wage. What do I do with the Mason jars?

I know the cleaning person could re-use both of them and the CEO's wife would probably look at me like I was crazy if I returned a cleaned but empty jar.

GENTLE READER: Espousing, as Miss Manners does, the belief that proper behavior is for the rich, the poor and everyone in between, is different (and truer) than saying that etiquette does not recognize means.

It does recognize them, although sometimes by intentionally ignoring them. Writing a thank-you note to the CEO's wife was an act of good manners. Writing the same thank-you note to the cleaning person accomplished two such acts: First, you thanked her for the gift; second, you did not confuse her economic status with her dignity as a person. None of this precludes you from performing an additional act -- of charity -- such as speaking to someone at work about seeing if the cleaning lady could get a raise.

You could also have returned both jars. Financial prudence also exists across people of different means.

(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 few hours before the small dinner party I was throwing for close friends, one guest called to ask if she could invite a mutual friend. I said, "Of course!" -- it was a buffet and we had more than enough food.

The new guest ended up arriving over an hour late. We were all hungry, and I was getting antsy. I was in the dining room when I was suddenly overwhelmed by strong odors.

I went to the kitchen to investigate, and what did I see but our late-arriving guest pulling crabs out of a cooler and handing them to another guest, who looked almost as confused as I felt. She told me the crabs are cooked and she has everything needed to shell them.

I was annoyed, but I said, "OK, add it to the buffet!" Honestly, I wish I had asked her to put them back in the cooler and leave them outside. I worked all day on a big dinner, and it was waiting.

I explained to the other guests that it would be a few more minutes before we could eat, that some crab needed to be shelled. The entire house now reeked of crab!

After about 20 minutes, I went back to the kitchen and some of the other guests had heroically joined the shelling party, and one of them was smartly bagging up the crab detritus.

Eventually we managed to get all the crab shelled and get the waste to the garbage. To the crab-bringer's credit, she cleaned up, and we were finally able to eat.

The dinner ended up being fun; we all had a good time, and people helped clean up after. The only thing is that the house was so smelly I could barely taste my food, and I'm just so resentful that my party was hijacked by such a party foul!

The person who brought the crab did say she thought it was maybe a potluck. I know the crab was expensive, and to her it was a nice gesture.

Should I have asked her to not serve the crab, or was it better to have an already late dinner even later and air my house out days after, knowing that we will laugh about this for years?

GENTLE READER: Fun then, and laughs later -- you can't be that upset. Nevertheless, you should know how to foil a party hijacker.

Miss Manners realizes that you were only trying to be polite by postponing dinner and allowing a guest to take over your kitchen. None of this was necessary.

You should not hold a meal for an unreasonably late guest. As an earlier etiquette authority, George Washington, once declared, it is rude to the chef. And, he might have added, to those starving people who were prompt, have drunk enough, and are contemplating eating the cocktail napkins.

What is required is to say, when the crab-bearing guest finally arrives, "I hope you don't mind, but we went ahead with dinner. I'm sure you wouldn't have wanted us to wait."

You had given that guest no reason to suppose the dinner was potluck. Miss Manners hopes that this has not come to be considered the default way of entertaining. At any rate, you could have told her politely that she was mistaken, and, as you ushered her to the table, that it would be better for the crabs to leave them in the cooler.

(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've found that I loathe staying in other people's homes. While it has become a fad to rent or be a guest in someone's home, it doesn't appeal to me. Even B&Bs give me the willies.

Even worse are visits to family when they extend invitations to stay in their home. I just don't feel comfortable. If I stay over, I always feel tense, no matter how gracious the host or hostess. In the worst cases, the accommodations are not something I would ever willingly choose, like a single bed or sleeper sofa.

The problem arises when I try to politely avoid these invitations. I usually use the excuse that I don't want to inconvenience them, but some people refuse to take that response.

Is there a more polite way to tell people I need my own space when it comes time for my nightly routine and bedding down without offending them?

GENTLE READER: "I'd love to see you, but I'm a terrible houseguest. Trust me."

They won't, of course. Politeness requires them to protest.

At that point, Miss Manners suggests saying, "Would anyone be bothered by loud noises in the night? Or sleepwalking?" (Note to lie detectors: This does not state that the person speaking shouts or sleepwalks.)

DEAR MISS MANNERS: My husband and I just received an invitation to an out-of-state wedding, and it reads, "Semi-Formal Attire -- Black, White or Black & White Required."

My husband doesn't own a black suit. We are traveling halfway across the country and staying at a hotel. We are already spending a great deal to attend this wedding. Not to mention buying a gift, too.

Do we need to buy a black or white suit just for this day? Would it be inappropriate to wear black pants with a white shirt and a black tweed jacket? And how about the tie, does it need to be black or white too?

GENTLE READER: What your friends are giving, in connection with the wedding ceremony, is a costume party, in which guests are instructed to dress as if they were attending a funeral.

As no one quite knows what "semi-formal" means, Miss Manners approves your suggestion, leaving the choice of black or white tie up to your husband.

(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.)