What is the biggest mistake Joe made in black beauty caring for black beauty?

One of the biggest mistakes Joe made in caring for Black Beauty was his failure to recognize and address the horse's physical and emotional needs adequately. His lack of experience and understanding led to instances of neglect, particularly in terms of proper grooming and providing a suitable environment. Additionally, Joe sometimes prioritized work over Black Beauty's comfort, which impacted the horse's well-being and overall trust in humans.