Pain, in many cases, is not a word people like.
However, pain is an important part of human beings. If we cannot feel pain, can humans still be considered human beings?
There is a saying in psychology that pain is a feeling that can be controlled. If you firmly believe that the injury you have suffered is not a big deal, you will not feel the pain.
Because of a failed, or too successful, self-hypnosis, Andy completely lost his ability to perceive pain and died as a result.
The reason why humans feel pain is to avoid danger. When the perception of pain is lost, any danger will lead to fatal consequences.
Perhaps it is because of this specialness that Andy received a unique system and a brand new life after his death.