Sleeping with head facing the South direction.
As per the Indian mythology, South is the direction of Lord Yama - The God of Death. Thus if we sleep with head facing North or feet facing the South direction, we would invite the lord of death. Ideally speaking, death does not come from any specific direction. Though this belief has a scientific explanation as well.
Taking into consideration, the laws and fundamentals of Magnetism, South Pole is the source of positive enegy while North Pole is considered to be the source of negative energy. If we sleep with our feet facing South then our head (brain) faces the North. If the already tired brain gets negative energy from the North direction, it will take more time for it to revitalize and work efficiently. Also, if this continues, the constant exposure of the brain to negative energy might reduce the efficiency of the brain gradually.
If a person doing stressful job sleeps with head facing South, he would get fresh comparatively faster and it has been noticed that the efficiency of such people has increased significantly.