Superstition refers to any belief or practice that is caused by supernatural causality, and which contradicts modern science. Superstitious beliefs and practices often vary from one person to another or from one culture to another. Common examples of superstitious beliefs in India include: a black cat crossing the road symbolizes bad luck, a crow cawing indicates that guests are arriving, drinking milk after eating fish causes skin diseases, seeing a mongoose symbolizes to be very lucky, and itchy palms mean that money is coming your way.