When did Ji Fa find Zhou Wang bad?

Before Zhou Wuwang's Western Expedition.

According to historical records, before Ji Fa became the leader of the Zhou Dynasty, he held an important position in the Shang Dynasty, and he knew something about the political and social situation of the Shang Dynasty.

He saw Zhou Wang's tyrannical and dissolute behavior and his cruel oppression of the people. This made Ji Fa realize that Zhou Wang was unfit to continue to rule, and decided to rise up, overthrow the Shang Dynasty and establish the Zhou Dynasty. Therefore, Ji Fa recognized the evil nature of Zhou Wang before the Western Expedition.