Characterization is one of the elements of dramaturgy and one of the things you learn, when you study it, is that there are flat or rounded characters.
Flat characters, which you find a lot of in Nollywood films, are those who are one dimensional they are either completely good or completely bad.
Rounded characters are more believable because although good or bad they also exhibit traits or elements of goodness or wickedness, strength or weakness.
They are more believable because they are real. People in real life are like that.
There is no one that is completely good or bad. Only God is good but when you over try Him you get the results Pharaoh and his people got.
Examples abound in the Bible of those who saw the red eye of God. God is love and He is also consuming fire.
Jesus gave Lazarus life but condemned the fig tree to wither. Nature embodies the very nature of God. Rain brings life yet in its wake we see destruction, without the sun vegetation will not grow yet too much of it scorches life out of them.
Human beings are the same, there is no one that is completely good or irredeemably bad. Looking at people through a narrow prism closes your eyes to the possibilities in them.
Open your eyes and look for the good in people. It is there if you look hard enough