Nellthu by Anthony Boucher (F&SF, August 1955) is a page and a half long squib that sees a man meet a woman from his schooldays. Although she was originally homely and untalented, she now has it all: wealth, beauty, talent, etc. When a servant brings the man coffee he realises it is a demon, and quizzes the creature on how she managed to get so much from three wishes. It turns out (spoiler) she did it with one—she made the demon fall “permanently and unselfishly” in love with her. A notion, not a story.
* (Mediocre). 450 words.