The main character Opal calls her friend David a name. Opal thinks she is joking however she soon finds out how her behavior has affected her friends feelings. Opal soon learns that calling her friends names is never a joke. Its Only a Joke is the first interactive book in the David and Opal series which provides a tool for children, educators, parents and guardians to explore behavior. This book is divided into three sections. Section one is a story which explores the behavior. This is followed by a question and answer, which give the child an opportunity to identify appropriate behavior. Then the book provides an opportunity for the child to reflect and discuss positive and negative natural consequences.