Personalities are characteristics that are shown by the villagers. They are divided into different categories and there are often at least 2 villagers with the same characteristic.
There are 6 known different personalities throughout the Animal Crossing Series, those being:
These personalities reflect on the villager of how they will treat you and other villagers. They all have their likes and dislikes, and can only relate to other villagers with a certain personality. It can either be difficult or easy to befriend with a villager but this will depend on their personality.
Related ThreadsWhat ACNL personality/animal would you be? - last post by @ May 13, 2014
WANTED: A person to go INTO ACWW - last post by @ Aug 21, 2006
Personalities - last post by @ Sep 16, 2007
Villager Personality Dynamics - last post by @ Sep 17, 2013
New Animal Personalities - last post by @ Oct 10, 2005