When looked at, the physical aspect of life is pain bad, and pleasure good. But pain or unpleasantness can be adapted to, so once its not painful or unpleasant , is it still considered bad? In the human mind it isn't. But if pain was meant to be bad, then why would we adapt to it. And why is pain bad if we just are going to adapt. It could possibly be the delusion of time, but adaptation will occur in a amount of time that is much shorter then the time living with the absence of pain or unpleasantness.
This only seems a human flaw because our minds are infected with the delusions of future and past.