DEAR MISS MANNERS: My son's ex-wife is pregnant with my grandchild. Their separation has been tense, especially with her family blaming my son for the breakup.

I have been invited to her baby shower, where her mother and family will be. I really don't feel comfortable attending, knowing how the family has treated my son, but the baby's mother really wants me there.

Should I go and, if not, how do I get out of it without hurting the baby's mother's feelings? If I do go, how do I handle the cool reception her family will give me?

GENTLE READER: That the person who will be rearing your grandchild still considers you family is something you want to encourage. Having recommended a cool reception for those who, unlike yourself, have done something wrong, Miss Manners can assure you that, though unpleasant, it is not fatal. And it is nothing compared to being dependent on a judge's order to see your grandchild.

DEAR MISS MANNERS: A friend returned a wedding RSVP with the "s" on "accepts" crossed out. My feeling is that he was very rude. You should not make what you think is a grammar check on a wedding RSVP. Am I correct?

GENTLE READER: This just shows how silly things can get when hosts attempt to supply the responses to their own invitations. (Miss Manners hates response cards, believing that decent people will provide their own answers, and delinquents will still not respond.)

If you were inviting people singly, "accepts" would be correct; if your friend was responding as a couple, it should be "accept." Miss Manners' guess is that it is the opposite, and that therefore you were both wrong.

If not, then your friend was not correcting you; he was simply making his own reply correct, which would be the proper thing to do.

DEAR MISS MANNERS: I am a businessman who frequently flies both domestically and internationally. I also happen to be an insulin-dependent diabetic.

I currently do my glucose testing in my seat. It does involve using a lancet device to get a drop of blood to test, but is fairly unobtrusive. Of course, all lancets, alcohol preps and test strips are stored in my test kit for proper disposal later.

Am I being rude to perform this test next to a stranger? Injections I perform privately in the plane's lavatory. In the airport, I use the counter by the wash basin, since most water closets have no room for insulin vials and other supplies.

Many people seem to stare and resent the fact of performing such a function in this space. I have also had children ask, "What is that man doing? Isn't that a bad thing?" (They're obviously thinking of their drug education classes.) Am I too self-conscious?

GENTLE READER: Absent an emergency, medical applications (like bodily functions and grooming) are properly done out of sight -- meaning in private or in a restroom -- unless they can be done so surreptitiously as to be unrecognizable as such. Miss Manners does not object to a pill taken at dinner, so long as it is not accompanied by a dissertation on your cholesterol.

The technology associated with diabetes is fast approaching this standard, although Miss Manners draws the line at drawing blood. Restrooms exist to provide a proper location for such necessary activities when away from home, and those who use them have no business monitoring the respectable, if sometimes unaesthetic, activities of others.

You may chose to tell children that it is a medical procedure, or ignore them and let their parents do that. Miss Manners would hope that any parents present would also resolve to teach their children to be more discreet with their curiosity.

(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: My Facebook friends have wonderful lives, and I am glad for them.

They have the best boyfriend/girlfriend/husband/wife. ("Yeah, be jealous," demands one young lady about the man in her life.) Their sons and daughters win academic and sports awards and are the most thoughtful beings on the planet.

They enjoy relaxing/exciting/exotic vacations. They build huge houses and plant lovely gardens. They enjoy laughter and parties with friends and warm and happy holidays with families. Their grandbabies become more and more adorable with each passing week.

They are thankful people, my Facebook friends, wanting to express their sense of gratitude for all the good in their lives. As some will put it, they are "blessed."

How does one know when one has crossed the line between "sharing" with a hundred or two of one's closest friends and boasting?

GENTLE READER: "Sharing" is a word best used to teach small children to allow other small children access to toys. The activity it now describes teaches the contradictory lesson of It's All About Me.

It is one thing to share good news with intimates who you know will rejoice for you, and for whom you have reciprocal empathy. Shouting from the housetops, however -- especially now that one is so easily able to reach untold numbers from there -- is another.

The test Miss Manners suggests applying is what reaction is expected from the recipients of one's announcements. Not everyone is so frank as the young lady who said, "Yeah, be jealous," but that seems to be the general motivation.

DEAR MISS MANNERS: My sister was hostessing a luncheon for 12, and to her dismay, a guest showed up with her own guest, announcing to my sister, "I knew you wouldn't mind."

There was the table set for 12, which was all it would comfortably accommodate, with the china service for 12 laid out on the best tablecloth. Horribly awkward!

I think I'd have been frozen in the doorway, but my sister let them in, despite her shock, and tried to conceal that she was laying a stray extra plate at a hastily added place. To my way of thinking, the guest should have been allowed to feel the full embarrassment of her actions ... if she was capable of it. Something along the lines of, "Your guest is welcome, but now you are the extra person for whom I have no space."

Please, Miss Manners, what would be the correct thing to do in such circumstances?

GENTLE READER: The wisest thing to do, whenever someone says, "I knew you wouldn't mind," is to run. No good will follow.

Unfortunately, your sister was not in a position to do this, as she was at home with guests. Miss Manners congratulates her for behaving politely, although she deeply sympathizes with your desire to chastise the presumptuous guest.

A compromise that might squeak through as accidental would be to say sweetly to the offender, "I'm sure you won't mind squeezing in a bit to make room for your friend," and seating her diagonally with the corner of the table pointed toward her.

(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: Is it appropriate for one of my friends to text my fiance exclusively with casual conversation? They were not friends prior to our relationship. I'm not asking if it's wrong considering I do not know the situation, but rather I'd like to know if there are any guidelines that deem it appropriate.

GENTLE READER: Are you asking if it is appropriate for your friend to be friends with your fiance? Or are you asking Miss Manners to tell them to stop it?

If your fiance is texting your friend while you are trying to hold a conversation with him, then guidelines would deem this to be rude. Otherwise, you would do well to be happy that everyone is getting along.

DEAR MISS MANNERS: I am a flight attendant for a major airline. As you can imagine, I deal with hundreds of customers each day I am at work. I try to present a polished look, and I feel that after 25 years in the industry, I still have maintained an excellent attitude.

What is really getting me down is when passengers comment on how I look. Nearly every day someone will say to me, "You look tired."

I do not know how to respond -- especially when I am not tired. I do not comment on their looks, so why is it OK for them to comment on mine?

GENTLE READER: Well, it is not, but they mean it to be sympathetic. They are thinking how tired they would be if they had to do your job, and offer this as a way of being sorry they are causing you more work.

But folks, telling people they look tired is really tiresome. Miss Manners begs everyone to cut it out.

DEAR MISS MANNERS: Should I refrain from asking my sisters-in-law, none of whom I'm really close to, not to come to the hospital waiting room to wait with me while my husband, their brother, has a relatively routine surgery? One of them is just nosy.

I'm sure they love their brother, but we never associate with them, and I just don't want the stress of having to make small talk with them. It's awkward, and I don't want to be hurtful -- I just want to be alone to wait.

GENTLE READER: Yes, you should refrain.

As inconvenienced as you might feel, this is their brother, and nosy or not, they have as much claim as you to wait for him at the hospital. Moreover, they've known him longer.

The stress of making small talk with in-laws is called being part of a family. But Miss Manners will allow you this: If the sisters ask if there's anything they can do for you, you may send them out for coffee -- if you do so graciously.

DEAR MISS MANNERS: Is it OK to cut, clean or clip your nails at a table at home or in a restaurant?

GENTLE READER: Only if you are eating alone, with the shades down, at a table no one else will have to use.

(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.)