Gift vs Ownership

In Amy-Jill Levine's book, Genesis, she writes about Cain and Abel.  Verse 16 of Genesis, Chapter 4, says, "Cain went away from the presence of the Lord and settled in the land of Nod, east of Eden. Levine disputes this, saying, "Well, no, he didn't. The divine presence is everywhere, including the land where Cain and his descendants will settle."

For me, that opens up the question: Why did Cain want to leave the presence of God? Look at Genesis 4: 10-15:

And the Lord said, “What have you done? Listen, your brother’s blood is crying out to me from the ground! And now you are cursed from the ground, which has opened its mouth to receive your brother’s blood from your hand. When you till the ground, it will no longer yield to you its strength; you will be a fugitive and a wanderer on the earth.” Cain said to the Lord, “My punishment is greater than I can bear! Today you have driven me away from the soil, and I shall be hidden from your face; I shall be a fugitive and a wanderer on the earth, and anyone who meets me may kill me.” Then the Lord said to him, “Not so! Whoever kills Cain will suffer a sevenfold vengeance.” And the Lord put a mark on Cain, so that no one who came upon him would kill him.

God explains the consequences of what Cain has done, and Cain finds it too much to bare.  He believes he has been driven away from the soil and that God will not see him anymore.  God contradicts this statement, and tells Cain that he is still under God's protection and care.

If Cain believes he "went away from the presence of the Lord," why would he do that? Did he doubt God? Did he feel guilty and didn't want to face God anymore? Was he angry about what had happened? Angry with God? Embarrassed? He has encountered divine mercy; why walk away from it?

Why do we walk away from divine mercy? We do, don't we?