I believe God had a fair reaction, he was very upset that Adam and Eve had been corrupted by the serpent - who I think represents evil. God gave Adam and Eve everything they needed and he trusted them to avoid one thing - eating from the tree of knowledge. I feel he had a right to be angry with them, because of their actions they now know things they shouldn't know, they took all the good and evil knowledge from the tree and it corrupted them. I believe the punishments he gave them ( “in pain shall you bear children”,“cursed be the ground because of you” ) were well-deserved.