Final answer:
Treating internal customers well can lead to opportunities and increase job satisfaction.
Step-by-step explanation:
One reason employers should treat internal customers well is that it can lead to opportunities and increase job satisfaction. By offering exceptional customer service to your manager, who is considered an internal customer, you can gain positive feedback and potentially open up new career prospects.
Additionally, treating internal customers well helps to maintain a positive work environment and fosters good relationships within the organization.