How to avoid "Festivus" (The airing of grievances)

Experts Say Family Fights Flare Up During the Holidays When There Is Unresolved Conflict
Excerpt:

It started with a blueberry scone. In their suite at a London hotel—with a view of the Kyoto Garden in Holland Park and the sound of harp music wafting up from the lobby—Heather Tobin’s two sisters both reached for the last scone on the breakfast tray at the very same moment. One sister grabbed it. The other tried to swipe it away. The two women, in their 20s at the time, bickered and then quickly moved on to insults: “Do you have jet lag, or is this your own usual selfish self?” one asked. “I’m glad I don’t have to live in the same house with you anymore,” the other shot back. Ms. Tobin, 30 years old at the time and vacationing with her family to celebrate her mother’s birthday, jumped into the fray. “This is ridiculous, we’re on vacation. Calm down,” she said. One sister threw the scone at her. The women stormed down the hall to their parents’ room overlooking the atrium lobby to complain. Their mother yelled at them for acting like children. Their father bellowed: “You are behaving like animals.” The parents fought with each other in the hallway about how to deal with their children. Eventually, everyone went back to their rooms and slammed their doors. Down in the lobby, the harpist, who had stopped the music because of the commotion from above, began playing again. “We all love each other,” says Ms. Tobin, now 45 and an antiques dealer in Kingston, N.H. “But we regressed.”

Comment: If you can't celebrate the joy of Christmas ... well ...   My basic principle is to not be a busybody .... not be in the business of others: How they spend their money, what career choices they make, where they choose to travel, the cars they choose to buy (houses too). In other words ... mind your own business! Wiki article on Festivus. There's even an official site!
See also: Surprise C-SPAN Caller Turns Out to Be Mother of Arguing Brothers