Somehow, it was an all-at-once realisation, that changed my perspective on many things. I can't quite say what the realisation is, but a couple of the perspectives that I gained are:
'Evil or bad' (not just in the moral sense) is not something, it is a lack where something belongs. Eg. Blindness is not something, it is the lack of vision.
The more complex something is, the less perfect it is.