Generally speaking, reactive power in a system is not good in any system (say transmission lines, etc.), but if somehow we decrease the reactive power to zero then will it be a perfect system? Or is decreasing the reactive power in a system to very low not good for that system?
The statement "reactive power is not good" is not always applicable. Yes reactive power does not contribute to any energy transfer but contributes to losses. However there are situations (notably fault recovery in a large power system) where reactive power is highly desirable.
EDIT: adding some info based on comments: Induction machines- motors and generators- need reactive power to function: in crude terms this reactive power sets up the "magnetic field" in the machine. Transformers draw reactive power too.