What are the advantages of elder brother bullying younger sister appropriately?

When a brother bullies his sister, he doesn't really bully. But a kind of love for my sister. In addition, under the bullying of my brother, my sister can exercise a strong heart. In the future, contact with society will not be timid, but also help to cultivate a cheerful personality. Therefore, the two children have been fighting since childhood, and their feelings will be deeper when they grow up.