Mother Yu's brother Qi Yue was a mischievous child back then. Seeing her bullying her sister, he and Big Brother Yu, who were also mischievous, played pranks together.
When they were discovered, Aunt would make a scene and run to Grandfather and Grandmother. Father Yu sided with his wife, warning Aunt that if she continued to behave outrageously, she'd be kicked out. So Aunt toned it down a bit, but still never stopped causing trouble.
Mother Yu tolerated her sister-in-law for her husband's sake. Father Yu felt guilty for having such a weird sister, so he was extra kind to Mother Yu, cherishing her for more than half of their lives.
Things didn't get better until Aunt married and left, Mother Yu could finally breathe a sigh of relief. But Aunt still couldn't sit still in the first years of her marriage, always running back to the Yu Family to stir up trouble. It was not until her husband gradually climbed up the ranks that she finally settled down.