Who disgusts me the most among "faithful"

It's not the person who lets God down, or even the person who lets Mary, Joseph or even Jesus himself down. And it's not even the person who lets down the Holy Spirit, even though that person risks never being forgiven by God. It's the person who lets down the infant Jesus, about whom even the Qur'an speaks tenderly. The person who lets down the baby Jesus is worse than scum.