This story describes what it means to be a bully and explains why someone might act like a bully. Here, the bully doesn't feel good about himself and, on op of that, he's jealous of Henry because Henry can play the violin.
This book is about a child who is frequently teased and picked on. It demonstrates the difference between joking with a friend or schoolmate and hurtful teasing. Many children have been teased like Nellie.
This book is about how anyone can be a bully - even a child who is smaller or younger than another child. Jake is ashamed because he is being bullied by someone younger and he doesn't want to tell anyone.