From their first encounter, he understands that he is dealing with someone unusual. Someone who succeeds in places where his ministers fail. Maybe that’s because he grew up with him in the palace (but we don’t talk about that). His demands are high, so he answers, “No.”
The second encounter is already more dramatic. Throughout Egypt you could tell something was happening—but he is the leader and he does not give in to blackmail. So he said “No.”
The crisis continues and still he doesn’t give up. The Torah tells us that the Eternal made his heart heavy, and perhaps it is telling us how the Eternal created us—with a heart that finds it hard to change, hard to let go, and for sure finds it hard to give up a leadership role.
Maybe the entire story of hardening Pharaoh’s heart was intended to remind us of the tendency of our hearts not to give in, not to let go, to cling to a position of authority and power, even when everything is falling apart. Perhaps we should read about Pharaoh and know when to let go and move on.