Why am I Lonely?

When “Ziad” is back at home, he notices that the jar in which he puts his pencils has disappeared. Immediately, he accuses his sister “Lama” of breaking the jar, while she has been cleaning his room. He uses some harsh words. This behavior has been repeated again with his friends. “Ziad” becomes lonely. But when he follows the advice of both his grandma and mom, he won’t be lonely any more… What is the advice?