My first sim to have an imaginary friend got along with the imaginary friend wonderfully. They had/have a lot of fun together playing games. When this sim became a teen, the imaginary friend even helped clean up around the house on it's own. They are grown up now, and she turned the imaginary friend real. They have a band together called "Imaginary Friends,"of course. They play neo-under-kids-gothic-pop.

However, the above sim's sister has an awful imaginary friend. She has the observant trait and noticed that the imaginary friend has the hot tempered and mean traits. The imaginary friend kept insulting, arguing, and generally making this sim feel bad every moment it could. It even booby trapped things around the house. They dislike each other, so the imaginary friend pretty much stays in an inactive doll form. She has the evil trait, so she may end up sticking it in a closet with a lit firework. She tried to leave it "mysterious drinks," but the imaginary friend always avoided them. I doubt she will spend the simoleons to make it real.