Some scientific studies on responses to different emotions seem to indicate that humiliation gives humans the harshest negative reaction. I would just on intuition agree with this.
People in certain cultures have literally committed ritual suicides to avoid or cleanse humiliation.
While ritual suicide seems like a harsh reaction to humiliation, in cases of suicides especially among children/teens, there very often is a component of bullying/humiliating of the suicide victim.

This would make sense to me at least.