DEAR MISS MANNERS: What is the proper thing to say to a co-worker who has just had breast augmentation done by choice?

It will be obvious that she had this done. Some of us who work in the office with her don't know what to say once she comes back to work.

GENTLE READER: Usually, those who claim that they "don't know what to say" mean that they are reluctant to use conventional phrases, not realizing that those are the time-proven best. However, in such cases as yours, it may be that they dimly suspect that they should shut up.

That would be Miss Manners' advice, immediately after saying, "Glad to see you back." There is no polite way of saying, "Wow, I see that your bosom is a lot bigger."

DEAR MISS MANNERS: I thought I had seen everything, but recently we received a wedding invitation via Facebook.

If that was not bad enough, it turns out that the wedding couple, both musicians, decided to have the ceremony in the context of a concert performance by them. The invitation indicated that because they have decided to rent a concert hall, in lieu of buying a gift, we would be required to buy a ticket to help defray the costs of the performance.

Again, because of financial restrictions, we were instructed that we could order food and beverages off a menu at our own expense, but cupcakes would be provided for dessert.

Last week we received yet another online notification indicating if we could not attend, we may choose to donate at various levels toward the couple's honeymoon. Depending on what amount we gave, the gift giver would be given a variety of different "thank you" responses from the couple.

I realize that times are changing, but we were flabbergasted by an invitation like this. While I don't expect people to go into great debt to throw an extravagant wedding reception, it also doesn't feel appropriate for guests to foot the bill.

We paid for our own simple but elegant wedding and reception, and kept it within a budget we could afford. I should add the couple are middle-aged, so I would think they would know better. Any thoughts on this?

GENTLE READER: Who are these musicians? Franz Liszt and Nellie Melba?

Even then, the price would be rather steep. Especially as you are expected to bring your own Peach Melba.

Because of the deft touch about different levels of thanks, Miss Manners will do this couple the courtesy of assuming that they meant it all as a joke. However, she feels obliged to warn them not to hope to make a living as comedians.

DEAR MISS MANNERS: My grandmother and I were at a restaurant that used paper napkins. Is it proper to put the paper napkin on the lap, or is that only necessary with cloth napkins? Please let me know as soon as possible.

GENTLE READER: How quickly were you hoping to trounce your grandmother?

Miss Manners' guess is that you will be disappointed, as she presumes that the lady is gracious enough to treat that pathetic piece of paper as if it were what it pretends to be.

(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, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: How often should a child have a birthday party during his or her childhood?

GENTLE READER: How often does the child have a birthday?

Perhaps you are confused by Miss Manners' rule that limits major adult celebrations to only three in a lifetime. This is so as not to overtax one's friends and appear childishly indulgent.

Miss Manners is more generous with actual children. She permits them a birthday party every year -- at their parents' discretion, and as long as there is no registry nonsense.

So then the question is, at what age is childhood finished? While she is inclined to leave this to the philosophers, her guess would be 18. Thus if a huge occasion is made of the 21st birthday, the next two could be scheduled at ages 50 and 100.

DEAR MISS MANNERS: When I have been in waiting rooms or similar settings and another person sitting next to me begins a conversation, I will acknowledge them and respond. However, there have been times when the other person will become negative and make comments that I considerate inappropriate or offensive to others, whether or not those others are there.

For instance, a lady sitting near me one day last week began complaining about people who do not speak English, and saying, "Don't you agree?" The next day, a man sitting next to me was saying that all young persons are lazy and expect a handout.

People have picked me out in a group as someone who wants to hear their opinions on politics, religion and just about everything else. Please tell me how I can politely get out of being drawn into these negative diatribes.

GENTLE READER: By not speaking to strangers, as you were once taught. They sometimes say strange things.

Rebuffing a talker in a waiting room or on an airplane cannot be as harsh as, for example, reacting to a stranger who has made an invitation to you on the street. In that case, Miss Manners advises walking away, if not calling the police.

But chatting with people in a confined situation such as a waiting room or airplane is optional. You can break in when the conversation turns unpleasant, or even tedious, by the same method for heading it off entirely: "Forgive me, but I can't talk right now."

DEAR MISS MANNERS: Now that my pregnancy is showing, many women will greet me with a short congratulations and then launch into some very frightening stories. Normally, I try to say, "Pardon me for interrupting, but I'm afraid you have me confused with someone else. I'm sure you would not want to share such a personal story with a complete stranger."

This works well with strangers, but I am at a loss for what to say to co-workers and acquaintances. Is there a polite way I can stop them from telling me their childbirth horror stories?

GENTLE READER: Pregnant ladies are so susceptible to sudden bouts of nausea that no one could blame you if you had to excuse yourself the next time you got whiff of a gruesome tale. Miss Manners suggests doing this often enough that they will catch on, but if they don't, you won't be around long enough to find out.

(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, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: I just received a sharp rebuke from a co-worker for sending him a personal email (following up on a prior conversation) at 5:45 in the morning. His reply stated only that "this exchange should not occur before 7 a.m."

I was taken aback by the tone of his reply. I have never exchanged emails with him outside of business hours before. Presumably, his smartphone alerts him of incoming email and my message disturbed his sleep.

I hadn't anticipated this -- I may be old-fashioned, but I still think of email as a desktop activity. Should I apologize for this apparent intrusion?

GENTLE READER: It used to be that surprise, late-night house calls were understood to be limited to those who could expect to be welcomed with open arms. Exceptions were made for emergencies, warrants and comic figures in Shakespeare plays.

But nocturnal knocks on the door and emails are not the same thing. You did not expect your co-worker instantly to act upon -- or even to see -- the early-morning email, any more than you would have expected an immediate response to a posted letter.

That the mail came early and set the dog barking, which in turn woke up the baby, who toddled down the stairs to the kitchen, terrifying grandma, who spilled her coffee, is not your responsibility.

That said, the best answer to your co-worker is to apologize and gently say that you were having the same problem until you discovered that it was possible to mute the sound announcing new emails on your phone.

DEAR MISS MANNERS: Is it necessary to bring the hostess of a potluck family dinner a hostess gift? Or is my contribution (as per her request), which is often more food than the hostess herself prepares, a hostess gift enough?

GENTLE READER: Hostess? What hostess?

Miss Manners has trouble thinking of someone who orders catered food from you as a hostess. And while you should not expect to be tipped if you also partook of these meals, the optional courtesy of another contribution is unnecessary.

DEAR MISS MANNERS: Due to health problems such as migraines, I am sometimes forced to cancel doctor appointments at the last minute.

When this happens, should I give a brief apology over the phone, send a written apology, or assume that the health professionals go on with their day relatively unaffected by my absence?

GENTLE READER: While it is reasonable to assume that doctors are familiar with -- and perhaps even sympathetic to -- the effects of illness, Miss Manners can assure you that they do not go on with the day unaffected by your absence.

They have been hit hard by the growing societal disregard for the commitment implicit in scheduling an appointment. Most medical offices now call beforehand to remind patients to show up. And an increasing number are registering their displeasure with absenteeism by charging fees for last-minute cancellations.

You do not want to be confused with patients who offer an invented illness to cover a less defensible reason ("I really don't feel like traipsing all the way downtown today"). A handwritten note of apology will reassure your doctor that you value her time. She is the last person you want suspecting you of feigning illness.

(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, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)