It is sin! That is what the dark page reminds us of. Sin is anything you think, say or do that does not please God, like lying, cheating, being selfish or hurting others. Sin can never be in Heaven.
The Bible says, “all have sinned” (Romans 3:23). That means everyone, you and me too. Everyone is born with a “want to” to do wrong. Nobody had to teach us how to disobey or to tell lies.
God says that sin must be punished. The punishment is to be separated from God for ever in a place of suffering.