The result of good or noble action is said to be sāttvika and pure. Of rājasa-action, the result is affliction, and of tāmasa-action, is ignorance (and delusion).
Krishna enumerates the spiritual laws under which sāttvika, rājasa and tāmasa persuasions lead our actions to their respective fruitions. These are as true and effective as the physical and chemical laws of nature.
Good and noble actions, involving no harm to anyone, beneficial to the society, fetch sāttvika results, namely peace, contentment and inner expansion. Everyone should aim at and strive to enhance sattva.
Rājasa actions are motivated by selfish desires and partial vision. These, invariably lacking thoughts of comprehensive well-being, inflict harm on others, and are detrimental to the society. Born of selfishness and greed, they ultimately bring affliction and torment to the performer also.
Tāmasa actions are steeped in ignorance and delusion. Tamas-domination does not allow one to think about the inner spiritual presence and its grandeur. Ignorantly one lives a sensory, material and outward life, often decrying the value of spiritual pursuit.