While the holiday gathering is supposed to foster closeness, connection, and an attitude of thankfulness, it can all too easily devolve into a raucous verbal sparring match, said clinical counsellor Dawn Schooler.
"Sadly, most of the time, we save our worst behaviour for the people that we're the closest to," said Schooler in and interview with CBC's On the Coast.
That's not necessarily our fault, she added.
Neurologically, humans are "literally wired to relate to people in historical ways," meaning decades-old sibling rivalries are more than likely to flare up in these kinds of situations.
How to foster polite dinner conversation
The best approach is not necessarily to enforce the old adage that we ought not to discuss politics or religion at the dinner table, Schooler said.
"If it is right, it's quite boring," she said. "Seven days away from a federal election, it's a big deal, and I would hate to see families completely shy away from it."
Instead, Schooler recommends laying down ground rules ahead of time.
Arguments are less likely to become explosive when parties are genuinely listening and being curious when discussing ideas.
In addition, it helps to decide on signals that will quickly redirect the conversation.
"When someone goes way offside, you throw your napkin on the table. That's done. Let's change direction," offered Schooler as one example.
How to defuse a heated situation
If the host isn't comfortable acting as a mediator, he or she should at least be prepared to say, "Turns out I didn't invite you here to hurt one another and be mean and awful. Shall we carry on with dinner in a little more civilized way?" said Schooler.
"Luckily, the Blue Jays are in the playoffs, so we can always change direction with, 'How about those Blue Jays?,'" Schooler suggested — unless you have friends or family from Texas.
Also On HuffPost: