Lulu and the Brontosaurus by Judith Viorst. From the very first page of the very first chapter, I loved this book. "There once was a girl named Lulu, and she was a pain. She wasn't a pain in the elbow. She wasn't a pain in the knee. She was a pain - a very big pain - in the b u t t."  This is the story of a spoiled girl who wants a Brontosaurus for her birthday, and she wasn't taking NO for an answer. When her parents fail to heed her cries and tantrums and there is no Brontosaurus, she sets off on her own to get one. Except when she finds him the Brontosaurus had different plans that did not include being Lulu's pet. Through her adventure, she is shown what an unpleasant little girl she has been and by the time she gets back home at the end of the book she has had an attitude adjustment.
This book was written by the same author of, Alexander and the Terrible, Horrible, No Good, Very Bad Day. I read it to my second-grade class when I wanted to show them the power of being nice. This story felt like a modern day fable. It has a moral message, while at the same time is a fun story. I find that children are often more able to see the poor behavior in others more readily than they can see it in themselves. This book is perfect for that.