Friends will row, fans bicker and spouses quarrel over the television remote during the World Cup - so here's how to avoid falling out over rugby.
A specialist says five basic principles of dispute resolution will ease most cases of World Cup rage, even if the All Blacks concede a fatal try in extra time.
You could be annoyed by how much rugby your spouse is watching, frustrated by the performance of your favourite player, or galled by a gloating rival fan.
"Supporters who are passionate about their team sometimes lose perspective in the heat of the moment and that is when it can turn ugly, particularly if alcohol is involved," said Massey University Dispute Resolution Centre director Virginia Goldblatt.
"In times of stress, heightened expectations and anxieties, disputes are more likely than usual to arise.
"The six weeks of the Rugby World Cup in New Zealand could provide a fertile ground for conflict."
From squabbles with international friends who support opposing teams to who is in charge of the remote control, Ms Goldblatt said the tournament was a hotbed of potential triggers.
It posed challenges to fans and non-fans alike as emotions ran high.
"Whether people are taking part in mass public events, at parties or at home, a certain level of control is needed."
The list of five principles to keep your cool begin by sounding a bit like psycho-babble - "separate the person from the problem", "build a golden bridge", "step to their side" and "expand the pie".
But the final principle needs no expertise to appreciate: "Go to the balcony".
"If you are losing control and the temperature in the room is hotting up, go outside, look at the scenery and breathe," Ms Goldblatt said.
Ideally, we would avoid conflict by anticipating it and not reacting, she said.
"When the argument is about the remote control, there are some quite sensible solutions.
"You could get a second television set in the bedroom for the person who doesn't want to watch the World Cup.
"[But] if conflict arises, intervene early - speedy, informal and constructive approaches to problem-solving are best."
Some situations, however, could require more advanced techniques.
"For intractable or entrenched differences - or the All Blacks lose - then some more advanced strategies are called for.
"We might have to go back to the drawing board for that."
Ms Goldblatt said conflicts during the tournament could go too far. "Domestic violence also increases, like at Christmas," she said.
For most people, the World Cup will make us seriously pissed off or elated for only a little while.
"But sometimes apparently trivial things surface very real problems in relationships or in the home," she said.
"The homes where people go to bed feeling very let down, but wake up in the morning and say, 'It's only a match', are fine.
"Conflict is inevitable. It's in how you deal with conflict."
Despairing for the All Blacks could also cross a line, she said.
"If the All Blacks losing is for you some kind of personal tragedy, then there's probably more going on than what's happening in the Rugby World Cup.
"And there might be a lesson in there for you."
Five expert strategies to avoid World Cup rage:
* "Separate the person from the problem" - If you are getting mad because a player from your team keeps giving away a penalty, don't blame him; it might be the game plan that needs changing.
* "Build a golden bridge" - When one of you supports the All Blacks and the other the Wallabies then find something you agree on: you both want South Africa to lose.
* "Step to their side" - Put the result into context; the other team might not have beaten yours for several years.
* "Expand the pie" - If you fight about the there being too much rugby on the TV, or whether to watch rugby at all, perhaps now is the time to get that second television.
* "Go to the balcony" - Finally, if you are losing control and the temperature in the room is heating up, go outside, look at the scenery and breathe deeply.