Why is Human Relations essentials to office environment?

Why is Human Relations essentials to office environment?
Better working relations between employees and manager (employers) is essential for the betterment of both the individual and organization.

Human Relations are so much essential to Office environment that many organization have a Human Resource department which performs some of the following tasks to improve human relations
PlanningPerformance AppraisalsTrainingEmployee EmpowermentJob EvaluationRewarding Performance
et.c