Nothing can wreak havoc on a holiday gathering like a few random button-pushing comments, especially among family members.
The verbal blunders, the hurt feelings, the ensuing chaos can take days or months - yes, even years - to forgive (we know you'll never forget). It's enough to have you muttering "Bah! Humbug" long before you ring the bell on the party.
But it doesn't have to be that way.
Just like eating your Aunt Agnes' special tomato aspic, a little preparation, some perspective and a touch of humor can get you through even the thorniest family moments.
Avoiding the "conversational land mines" in the first place might be the easiest solution, said Debra Fine, author of "The Fine Art of Small Talk." Preparation is key, she said.
"Remind yourself what you already know," she urged.
By taking a couple of minutes to review who will attend the event and what you know about theose people, you can find comfortable points of discussion, Fine said.
"These are ways to keep your foot out of your mouth," she said.
You can remedy deafening silences and awkward encounters with prep work, too.
If you're new to a group or your family invited newcomers this holiday, prepare a few conversation starters.
Fine suggests something such as: "Tell me what keeps you busy" or "What are your fondest holiday traditions or memories?"
Open-ended questions keep conversations flowing and eliminate the oh-so-enlightening "yups" and "nopes."
If you've been out of touch with certain friends or relatives, keep questions general and avoid specific references to jobs or boyfriends or other potential lightning rods.
A question that seems neutral such as "How's your job at Enron?" might lead to an uncomfortable disclosure and discussions better avoided during the holidays. Instead, Fine suggests something broader such as, "Bring me up to date - what's been going on with work since the last time I saw you?"
But what if you're the one put on the spot?
"Just prepare yourself not to react emotionally or defensively," Fine said. "If you can use humor, that's the best."
Then be a good guest and change the subject, she said.
One reason Fine thinks the holidays are ripe for blow-ups is people don't think before they speak and revert to old family dynamics.
"With our family, we feel like there are no parameters, and we forget who we are now and revert to who we were," Fine said.
Perspective and diplomacy can help maintain harmony, said Cindy Grosso, owner of the Charleston School of Protocol and Etiquette.
"You are there to celebrate, to have a good time with your family," she said, so personal issues should take a back seat during the holidays.
Be gracious to your host, and don't start a fight or make others uncomfortable. If you have an issue, she said, leave it at home or don't attend.
Eating lots of sugar and carbohydrates kicks our brains into a "high-pitch state," he said.
"This causes people to be more sensitive and less likely to let things slide, let things go," Phillips said.
A few glasses of wine or holiday toddies can complicate things and create a dangerous combination with lowered inhibitions, he said.
And don't be surprised if someone who upset you in the past continues to behave in the same manner, he said.