Avoiding Bias:

The Chidushei Harim zy"a notes that although Korach was one of the carriers of the Aron, and he had ruach hakodesh, and he was a tzadik and an old man of 130 years old, he still was jealous of Elitzafon ben Uziel, and this led to his downfall. This small bias destroyed him.

This teaches us how much a personal bias can bring a person down. On the other hand, one good action can uplift a person to great heights.