This relationship is not to be confused with the 100% friendship status on the Compatibility Tester.
If two best friends have an argument that lasts for a while, a sting will play with the Miis having worried faces and a message will pop up saying "[Mii 1] and [Mii 2] became friends." The two Miis will no longer be best friends, and will possibly be under Kinda Getting Along or Not Getting Along.
- Sometimes, the best friend of a Mii can be used to stop a huge fight if it occurs. Otherwise, it will be a random regular friend of both fighters.
- It is possible for two Miis to become best friends offscreen without the player watching. Goes the same for them losing their best friend status.
- it is possible that a Mii can dump their best friend by becoming best friends with another Mii. This will not put the Mii dumped in sadness though.