I suggest you to watch it before reading this or reading any of the diatribe or the review or the criticism. There are always those kind of people who flatter your pride when you think and tell that you are bad. Yorgos Lanthimos made you put yourself into the deer, "A Sacred Deer". Considering that the Sacred Deer is actually belongs to the Greek Mythology makes it somehow more clear or I should say; complicated. If you are that kind of man who like to be flung in its face, you will enjoy watching the idea of the humanity is finished in today's dark world. If you are not you will either suffer during 2 hours or you will leave it undone.
Lanthimos shows the dark and the true side of the human psyhcology in the movie as lancing the strongest crust by using the irony of giving the choice or freedom of killing on condition of saving. Even though every individual has at least this cruelty of enjoying to watch the last scene when the father chooses the victim, all their crust provide to show this joyment on emotions during the scene. This is the reason for rejection of the idea; there is always darkness just behind the goodness. Lanthimos fool the audience as creating an atmosphere has strong bonds with reality, gives the teenage boy a supernatural power for destroying the family. In the movie, you can see that all the main characters are sick. Parents are having sex in a sick way, the wife of the guy died during the surgery is molesting to the doctor who caused her husband to die, the daughter of the doctor is flirting with the teenage boy who is killing her family. Most of the time it is unacceptable for people to put those characteristic features into the every individual in the society. The wisdom of the teenage boy; offering the doctor to get together with his mother instead of taking the revenge is the reflection of the sacredness or the goodness. After the rejection, the teenage boy uses his super power to destroy his family for revenge and yet giving him the chance of selecting which is actually a mercy of a psycho. However, the psycho is the only one who can see the merciness. Mainly, it is seen as a reflection of darkness. The doctor kidnaps him but yet he can not touch the boy because he showed his invulnerable by biting his own arm. As it has many scenes that actually shows the every characteristic into us, we are systematically conditioned to reject of the darkness and pray for the goodness which is actually including the darkness " The mother kneels and kisses the teenage boys feet, putting him into a God position and then releasing him." in other words, we are as humanbeings always consider and admit as Holy and obey to the things that we can not beat.
Science kneeled and kissed the feet of the spirituality.