The Berenstain Bears Get in a Fight by Stan and Jan Berenstain
This Berenstain Bears story shows kids how to "hug and make up" after a fight. Realistic and amusing, it imparts a moral without preaching at the reader.
If you're looking for popular children's books that teach life lessons in a way that's fun and easily remembered, check out the bestselling Berenstain-Bear series by Jan and Stan Berenstain.