The Problem: Your sibling constantly passes judgment on your career or your kids.

Just Get Over It? No. You don’t have to stand for it. By putting you down, he’s probably trying to make himself feel better.
What to Do: “Be assertive, but not defensive,” says Peter Goldenthal, a family psychologist based in Wayne, Pennsylvania, and the author of Why Can’t We Get Along? Healing Adult Sibling Relationships (Wiley, $15, www.amazon.com). Contain the urge to match his tone and rudeness. “You may not be able to change his behavior, but you can change the way you respond,” says Marcia Millman, a professor of sociology at the University of California, Santa Cruz. Tell him what you think, then “try disarming him by telling a joke or mentioning something about him that you genuinely admire,” she says. You can choose to act like an adult, even if he can’t.
Sample Script: “Actually, I’m really happy with Jimmy’s choice of major. He should be able to find just as many job opportunities with an economics degree as you did with your business degree.”

The Problem: Planning the family party or buying the group gift always falls to you.

Just Get Over It? Yes. You were the type A kid, right? And siblings always looked on. They’re probably not lazy now. They’re just repeating those childhood roles.
What to Do: Don’t do everything yourself. Give your siblings a chance to pitch in, and make them feel appreciated. “Your sibling probably needs to feel important,” says Goldenthal. “Some people need a lot of acknowledgment or flattery.”
Sample Script: “I’m really going to need your help for this party. You have such a beautiful eye for design. Do you want to handle the invitations or the decorations?”

The Problem: Your sister’s obnoxious husband grates on your nerves.

Just Get Over It? If you want to remain close to her, yes.
What to Do: Try to understand what she sees in him, and be happy for her. Do not approach her with a “Why I hate Steve” laundry list, which will just offend her. “Anything you say will be seen as a judgment of her judgment,” says Millman. “What matters is if she’s in love with her partner and her partner loves her and makes her happy.” Grin and bear it, and arrange occasional outings alone with her to spare your gritted teeth. (The exception to this rule: If you suspect any kind of abuse, speak up.)
Sample Script: “Do you think we can go holiday shopping alone today?”