Your Miis are like real people, with emotions, hunger, and even their own dreams.
You can tell that they’re sleeping or napping because they will have closed shutters in their apartment. From there, you can access your Mii’s dreams. Afterward, you’ll receive an item after the dream, anywhere from fish sticks to a hamster suit.
Some dreams are interactive, such as the security camera (that utilizes the 3DS self camera function), and other dreams such as the hamster one that allows you to pull strings which brings out Miis hiding like hamsters.
You should also note that some dreams are never ending, such as the hide-and-seek one if the mii is never ready or the driving one where your mii is a bobble head.
Very often, the dreams will repeat and you will receive the same item, sometimes it will be in a different color, as in the case with the straw hat or ninja suit..
You can access the dream database using the Hypnotizer, but you will not receive the affiliated treasure item. It’s simply a collection that shows you what dreams you have dreamed before. Now take in mind, you can only get a hypnotizer through solving mii’s problems. I prefer using the hypnotizer to calm my mii down after they get in a fight with someone and then seeing what dreams I already have or how many more dreams I am missing.
I’ll finish this off with some great dreams: