Good or bad is a human duality (up-down, right-left, top-bottom) concept based on our beliefs.
For instance, most, generally, believe God is good. But, if He punishes us, we may feel the punishment is bad or God is being bad towards us.
We also say Satan is bad, but if Satan awards someone for something, that person may think Satan is being good.
The opposite also applies... depending on what side we're on. We may think God's punishment to another is good or deserving, whereas Satan's reward to someone is bad.
Yet, what if our belief of good and bad is tested, by someone we see as good, when asked to do something we feel is bad or evil? Would we still do it?
This is why humans live in a chaotic existence. Not only are we fighting what we see as good or bad in others, we're, constantly, fighting those feelings within us: the battle of heart and mind.
However, the line between the good or bad duality will begin to fade when we understand universal law and order: as in the Chinese philosophy of the yin and yang where it's believed that seemingly contrary forces may actually be complimentary.