Sometimes if a player is watching a Mii's apartment, two Miis can be seen talking to each other for a while. They will face each other and do various gestures as they talk, showing speech bubbles with ellipses in them. Although it is hard to tell what they're talking about because of the whooping sound effect they use when they talk to each other, their gestures will indicate how they are talking (normal, happy, sad or angry), sometimes changing their facial expressions for half a second. If they show positive gestures, they could be happy with each other; if they show angry gestures, they could be having an argument. Their conversations could raise or lower their relationship level, depending if it's a good conversation or an argument. If they show neutral gestures, their relationship status will not change.
There are four types of conversations: normal, happy, bad and argument.
- Normal: The Miis are talking normally, without showing emotions. Relationship stays same.
- Happy: The Miis are in a really good conversation, shown by them bobbing their heads and arms as they talk, showing happy expressions, and sometimes laughing. Miis could become best friends if a happy conversation lasts long enough. Relationship increases.
- Bad: One of the Miis shows a sad face and appears to be upset, appearing apologetic, leading the other Mii to calm them down. Relationship decreases.
- Argument: One of the Miis shows an angry face while the other Mii talks, leading it to throw a temper tantrum when it's their turn to speak. Miis could fight if an argument happens long enough. Relationship decreases.
Gestures the Miis make:
- Standing still and bobbing their head (Neutral)
- Leaning forward slightly, with arms out (Neutral)
- Laughing loudly (Positive)
- Folds arms to the side (Neutral)
- Angrily stomps their feet while pounding their fists (Angry)
- Hanging their head sadly (Sad)
- Waving their hand over their head in apology (Sad)
If the Miis are not best friends and show happy faces and gestures long enough, they will become best friends. But if they show angry and sad faces long enough, complete with throwing temper tantrums, they will instantly fight, either normal or huge.
Sometimes, when sweethearts or spouses are in the same apartment, they will talk romantically, as shown by them sitting on the ground with hearts appearing, and both repeatedly showing happy expressions. When Miis talk this way, they will not argue or freak out.
Conversations are also used in Miitomo, but are only temporary. If a Mii comes over to the player's apartment, they will talk to each other, sometimes laughing or looking surprised. If the player selects the visiting Mii and is finished talking to them, they will immediately exit.
An argument is the angry version of a normal conversation. It occurs when two Miis are together in the same apartment, with a normal conversation leading to one of the Miis showing negative reactions like throwing a temper-tantrum while the other Mii sulks in sorrow. One hint of a possible argument about to break out during such a conversation is if the listening Mii has an angry expression flicker on their face for half a second as the other Mii talks.
If both Miis display this temper-tantrum animation for large amounts of time, it will lead to an immediate fight, and attempting to either shift to another apartment or enter the apartment depicting the Miis arguing angrily will cause it to occur instantly. When the fight occurs, both Miis will shake angrily as a horror sting plays, followed by the caption "[Mii 1] had a fight with [Mii 2]."
If a fight doesn't occur, it will drop a Mii's relationship by one or several levels (possibly enough to bring it from either the highest two stages of relationships to the lowest instantly), and if the number of maximum fights are already present (three), the two Miis will simply stare at each other with their "sad" expressions while the "Fight Start" sound effect plays.
Sometimes, but not often, the two Miis will instead talk normally with one another and show positive gestures, which raises the relationship level as opposed to lowering it. However this type of conversation is uncommon and is more likely to curve into an argument.
Arguments can only occur if the game is left idle at Mii Apartments and the player or the game itself changes the focus into the apartment of two Miis chatting, leading to their friendship/relationship status tanking, regardless of how long the argument lasted before the player interferes. They cannot occur if the player is in the overworld or at Mii Homes.
- If the Miis are arguing for a long time, shifting apartments or entering the current one being viewed will cause the fight to immediately start. This goes the same for them becoming best friends.
- If the player shift apartments during a conversation, the conversation will end.