If I'm on about the same thing you are, it's when you've just started a new town and the game fills your town with villagers. It will always give you the personalities you are missing, such as uchi and smug.
So, what a lot of people do is, they tt until they are missing say a smug villager, then they do the camper reset trick and check which smug villager has moved in.
Because you aren't saving, each time you do this the smug villager is different. You can use it to get villagers of personalities you really want, like Henry, Marshal or Julian.