It is always a question to the humanity which is bad which is good.
But are "good" "bad" absolute or does those change with time?
Good/Bad means Dharma/Adharma, then yes Dharma does change with time. There is something called Yuga Dharma (duties prescribed for a certain Yuga).
anye kritayuge dharmAs tretAyAm dwApare apare |
anye kali-yuge nrinAm yugahAsAnurupat ||
Manu Smriti 1.85. One set of duties (is prescribed) for men in the Krita age, different ones in the Treta and in the Dvapara, and (again) another (set) in the Kali, in a proportion as (those) ages decrease in length.
But, generally, the usual rules that define good/bad remain the same. For example, killing someone, stealing are bad irrespective of which age you have committed those acts in.
Similarly, providing food to the hungry etc are counted as good acts all the time.
Good and Bad are opposites and are part of Wisdom/Satva and Ignorance/Tamas
If one wants to abide in the thought-free state, a struggle is inevitable. One must fight one’s way through before regaining one’s original primal state. If one succeeds in the fight and reaches the goal, the enemy, namely the thoughts, will all subside in the Self and disappear entirely. The thoughts are the enemy. They amount to the creation of the Universe. In their absence there is neither the world nor God the Creator. The Bliss of the Self is the single Being only. When Prahlada was in samadhi, Vishnu thought within Himself: “This asura being in samadhi, all the asuras are in peace. There is no fight, no trial of strength, no search for power, nor the means for gaining power. In the absence of such means for power - yaga, yajna, etc., i.e., the gods are not thriving; there is no new creation; nor even is any existence justified. So I will wake him up; then the asuras will rise up; their original nature will manifest itself; the gods will challenge them: the asuras and others will then seek strength and adopt the means for its acquisition. Yajnas, etc., will flourish; the gods will thrive; there will be more and more of creation, more of fight and I shall have enough to do”. So Vishnu awakened Prahlada, blessing him with eternal life and jivanmukti. Deva-asura fight was resumed and the old order of things was restored so that the universe continues in its eternal nature. D.: How could God Himself wake up the asura element and bring about constant warfare? Is not Pure Goodness the nature of God? M.: Goodness is only relative. Good always implies bad also; they always co-exist. The one is the obverse of the other.
The creation is on 3 gunas Satva, Rajas and Tamas of Prakriti which stands as a superimposition on Nirguna Purusha/Self as also explained in Bhagwat Geeta
Bhagavad Gita 14.5 O mighty-armed Arjun, the material energy consists of three guṇas (modes)—sattva (goodness), rajas (passion), and tamas (ignorance). These modes bind the eternal soul to the perishable body.
Bhagavad Gita 14.6 Amongst these, sattva guṇa, the mode of goodness, being purer than the others, is illuminating and full of well-being. O sinless one, it binds the soul by creating attachment for a sense of happiness and knowledge.
Bhagavad Gita 14.7 O Arjun, rajo guṇa is of the nature of passion. It arises from worldly desires and affections, and binds the soul through attachment to fruitive actions.
Bhagavad Gita 14.8 O Arjun, tamo guṇa, which is born of ignorance, is the cause of illusion for the embodied souls. It deludes all living beings through negligence, laziness, and sleep.
Bhagavad Gita 14.9 Sattva binds one to material happiness; rajas conditions the soul toward actions; and tamas clouds wisdom and binds one to delusion.
Bhagavad Gita 14.10 Sometimes goodness (sattva) prevails over passion (rajas) and ignorance (tamas), O scion of Bharat. Sometimes passion (rajas) dominates goodness (sattva) and ignorance (tamas), and at other times ignorance (tamas) overcomes goodness (sattva) and passion (rajas).
Bhagavad Gita 14.11 – 14.13 When all the gates of the body are illumined by knowledge, know it to be a manifestation of the mode of goodness. When the mode of passion predominates, O Arjun, the symptoms of greed, exertion for worldly gain, restlessness, and craving develop. O Arjun, nescience, inertia, negligence, and delusion—these are the dominant signs of the mode of ignorance.
Bhagavad Gita 14.14 – 14.15 Those who die with predominance of sattva reach the pure abodes (which are free from rajas and tamas) of the learned. Those who die with prevalence of the mode of passion are born among people driven by work, while those dying in the mode of ignorance take birth in the animal kingdom.
Bhagavad Gita 14.16 It is said the fruit of actions performed in the mode of goodness bestow pure results. Actions done in the mode of passion result in pain, while those performed in the mode of ignorance result in darkness.
Bhagavad Gita 14.17 From the mode of goodness arises knowledge, from the mode of passion arises greed, and from the mode of ignorance arise negligence and delusion.
Bhagavad Gita 14.18 Those situated in the mode of goodness rise upward; those in the mode of passion stay in the middle; and those in the mode of ignorance go downward.
Bhagavad Gita 14.19 When wise persons see that in all works there are no agents of action other than the three guṇas, and they know me to be transcendental to these guṇas, they attain my divine nature.
Bhagavad Gita 14.20 By transcending the three modes of material nature associated with the body, one becomes free from birth, death, disease, old age, and misery, and attains immortality.