I would like to add that Davies found it very important that many people have superstitions and do not even realize it. They may think that other people are silly because they have superstitions but in fact have superstitions of their own.
One reason that people are superstitious is because being that way gives them a sense of control. They feel if they do something a certain way then they may be preventing something bad from happening.
Here are a few more examples for you. Vain observances include throwing salt over your shoulder after spilling it. Divination is reading the daily horoscope in the newspaper. Idolatry is having a rabbits foot for good luck. And lastly, improper worship of a deity may be bargaining with God to get something you want.