What made Pharaoh the way he is?
The Bible describes humanity's duality: we are made by God in His image and yet the doctrine of original sin calls us enemies of God.
Manifestation of sin in the everyday sinner:
1. "My desire trumps God's commands."
2. When God makes threats or warnings, we may respond in anger, or ignore them, or refuse to believe them. These threats give opportunities to change behaviour and find mercy. We can avoid pain and suffering if we would repent and take them to heart.
3. We can be shown truth/evidence, but if it contradicts our desires we refuse to change (we ignore, downplay, reject).