Cinderella is a classic example of this very thing.
In Cinderella, Cinderella was enslaved in her own home by an evil stepmother and her two ugly stepsisters. It's implied that Cinderella is beautiful compared to all of them. A fairy godmother intervenes and hands Cinderella the chance to go to the ball as she wanted, pretty much handing the main character the very thing she wanted. (Her step-family would not let her go.) At the ball, the prince (unnamed) falls in love with her, but Cinderella's fantasy ends at the stroke of midnight. She leaves her glass slipper behind when she runs home in shame. Later, the prince is looking for her, and he eventually finds Cinderella despite how the stepsisters tried to cheat their way into marrying the prince. (Those two did some weird things to their feet...) In the end, Cinderella and the prince live happily ever after. The end.
A child reading Cinderella may assume that the prettiest of girls, even if they have hardships, can have anything they want handed to them by someone from pity or admiration. Cinderella is given a night of romance in a fancy dress (possibly from pity) and a life of luxury (most likely from the prince's admiration of her). This child will then grow up thinking, because she is beautiful, that she can have or obtain anything she desires.
Boy, is she up for a major wake-up call in her future!
