Does superstitions practically exist

Many superstitions do have a practicla basis, such as not walking under a ladder, or not breaking a mirror. These are both supposed to give a person seven years of bad luck, but in reality they are also simple safety hazards.
Other superstitions, such as throwing a pinch of any salt you spill over you left shoulder, are based entirely in religion. The pinch of salt you throw is intended to frighten off/hurt the devil that will appear when you spill salt.