DEAR HARRIETTE: Three of my close friends and I were invited to a mutual friend's party. I made the assumption that our fourth close friend was also invited since we all know each other well. I was wrong. Because of my assumption, I casually asked this friend what she was wearing to the party, as we always do before we are getting ready for an event. She didn't know what I was talking about. The more I explained myself, the worse it got. I quickly figured out that I had made a mess of things.

I know the hostess doesn't have to invite anybody she doesn't want to invite. I made an honest mistake, but now our friend is feeling left out. What can I do to fix it? -- Party Pooper, Racine, Wis.

DEAR PARTY POOPER: You did make an honest mistake, one that I hope will teach you not to talk with others about outside events unless you are sure they've been invited.

It is not unusual for a host not to invite every single friend in a group to an event. I wonder if friend No. 4 was singled out and not invited for a reason. Perhaps there is an issue between her and the hostess of which you are unaware. Or your friend just may not have made the guest list. Or it could have been an oversight.

Rather than digging an even deeper hole, stop. Apologize for putting your foot in your mouth. Tell your friend you are sorry that you made things awkward. Don't create a long and drawn-out scenario by evaluating the situation with your friend.

You may want to tell the hostess that you told your other friend. Then if it comes up, she won't be blindsided.

To party givers I will say that it is important to think about who is on your guest list. If you invite a group of friends, be sure to include all the key members. Leaving out one member of a group usually leads to discomfort -- the opposite feeling you want to evoke as you prepare for your celebration.

DEAR HARRIETTE: My mother came to visit to help me with a project I was working on. We had a great time together, but she also was supercritical of the way I live. It's fair to say that I am not the neatest person, and she let me have it. I didn't want to hear it, and I was pretty short with her when she made her comments. Should I apologize? -- Embarrassed, Washington, D.C.

DEAR EMBARRASSED: Mothers are often right. Absolutely apologize if you were rude to her. Admit that you know you need to clean up your act. If you have the courage to do so, ask your mother for suggestions on how to approach your mess. She may be able to provide some insight. Beyond that, get organizational support if you can afford it. Strategic help may be the answer to your problem.

DEAR HARRIETTE: I met a guy at a social event who cornered me and told me the saddest sob story about his life. I wanted to be nice to him, but it was the wrong setting to have that type of discussion. Plus, I'm not a therapist. He was so persistent that he got my card. I don't want to continue the conversation, though. I cannot help him. He needs professional help.

When he calls, which I'm sure he will, what should I say to him? I don't want to hurt his feelings. He's already fragile, but I need to protect myself as well. -- Cornered, New York

DEAR CORNERED: When this man calls, tell him immediately that you think he deserves to have professional help to support him through this time in his life. Admit that you do not have the skills to help him. If he presses you, as is likely, firmly tell him that you were happy to meet him at the event but that you cannot get together.

In the future, if someone corners you at an event, you can end the conversation. You can say something kind to the person about his or her life and then add that the event is the wrong setting to discuss such matters. Say goodbye and walk away. If asked to get together privately, just say you can't.

DEAR HARRIETTE: I am so mad at myself. I didn't trust my instincts and I am now paying the price. I met a woman who seemed to have it together but was a little down on her luck. She asked me if I could find any work for her. I talked to her a few times and she seemed nice and efficient, although she definitely talked too much. I had a project that I thought would be a home run for her. She would have to be social and professional at once. Part of me thought she might be too talkative, but I decided to give her a chance.

What a mistake. She stood around talking for about an hour and a half at a function where she was supposed to be working. When she wasn't talking, she was checking her email or eating. Everybody else I had brought into the project was busy working. When I mentioned her behavior to her repeatedly, she didn't improve significantly. I'm definitely not going to hire her again, but I wonder if I should say something to her about her behavior. --Disappointed, Rochester, N.Y.

DEAR DISAPPOINTED: The key lesson for you is trusting your instincts. I get that you want to help people in need, but it works only if you match people to their skills and abilities. If the voice inside is telling you "no," follow its lead.

It would be so generous for you to talk to this woman and describe your observations about her behavior to her. Especially since you know that she has been unsuccessfully looking for work, you may want to share your understanding about what may be keeping her from employment. Slacking off on the job is at the top of the list. She may get mad at you, but your charity in this way is priceless.

DEAR HARRIETTE: My husband and I have had cats for a long time. We have a granddaughter who is 11 years old. She has recently developed an allergy to cats. She used to visit often, but her parents say she and her sister are no longer allowed to come to our house.

I know that sleeping over is probably out. But couldn't she take some medication or do something else that would allow her to come for Thanksgiving or Christmas? At most, it would mean coming over for two or three hours every few months. We have a big house, so the cat could be put in one of the upstairs bedrooms while she is here.

Their house is a long drive, and we are getting older. We are in our 70s. -- Miss My Grandchildren, Glenview, Ill.

DEAR MISS MY GRANDCHILDREN: I feel your pain -- and theirs. As someone who is severely allergic to cats, I fully understand why the parents decided not to allow the children to come to your home.

As clean as your home may be, pet dander is nearly impossible to remove completely. Putting the cat upstairs doesn't eliminate its lingering presence throughout the house. For some people, simply walking in the door of a space that has cats triggers a serious reaction in their bodies.

Can your granddaughter take some kind of medication? Maybe. You can ask her parents if they could visit the doctor and find out if there's a way she can visit you without compromising her breathing. But if the parents don't want to do that, perhaps they can schedule regular times to pick up you and your husband to come and visit with them. That way, you wouldn't have to endure the long drive and could still be with your precious grandchildren.

DEAR HARRIETTE: My cousin moved to my town about a year ago, and she has been living with a friend. She needs a new apartment or someplace to stay. She hasn't directly asked me, but I think she wants to. I'm sure my husband would not want to do this. We don't have much room in our small apartment.

But I keep thinking of my grandmother. She used to take in everybody in the family if they needed food or shelter. Am I being selfish by not inviting my cousin to live with us for a while? -- Troubled Relative, East Orange, N.J.

DEAR TROUBLED RELATIVE: It used to be that families took in loved ones, no questions asked, for as long as needed. Some families continue to do that today. This does not mean that you are required to do so.

You must talk with your husband and make a family decision about how you can support your cousin. If she is in desperate need, you could consider inviting her to stay with you for a limited, specific period. You could help her find housing. Or you could just stay close to make sure she is OK during her search. Do what works for you, but do remain connected to her.