Good and evil are two sides of man's experience of existence. They are subjective but do exist and are inseparable. Fortunately one can choose to jump from one side to the other. But what can seem good to one may feel evil to another. With times perceptions too change. Therefore one is always prone to error in judgment. Suffering is a product of this perception of error and evil. Gods and devils need not be created to sit in judgment upon simple human nature. Plain human attributes of wisdom and compassion contrasted with ignorance and greed are effective enough to make a difference between heaven and hell.
Just imagine what see change can be effected by humanity if the best of human nature could be embraced and the fictitious firmament of heavens, hells and purgatories could be abandoned.