Johannes Brahms

Those who enjoy their own emotionally bad health and who habitually fill their own minds with the rank poisons of suspicion, jealousy and hatred, as a rule take umbrage at those who refuse to do likewise, and they find a perverted relief in trying to denigrate them.

By irreducibly complex I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning.