Most superstitions--like not letting a black cat cross your path--don't make sense, so why do so many of us repeat the same rituals over and over? It may have to do with evolution.
The rituals that we do to bring us luck are habits, and it turns out that pigeons develop habits as well, which is why psychologists who are interested in superstition study them. Psychologist B.F. Skinner thought superstitions started when something good (or bad) happened after a person had done some sort of movement, such as scratching his elbow. Since the person didn't understand what caused the good luck, he attributed it to the elbow scratching and made that movement every time he wanted something good to happen. We see that in baseball games all the time, when a player makes ritualistic movements before getting up to bat. We're all trying to placate the "gods of luck."
Modern man has a scientific education, so while we KNOW that there's no connection between crossing our fingers and having a good outcome, we do it anyway, because it worked once, so it may work again. As Tom Stafford writes in BBC News, "We cling to these habits because we--or ancient animal parts of our brains--do not want to risk finding out what happens if we change."
The only thing WE'RE superstitious about is why it's so darned hard to LOSE WEIGHT! If that's your problem too, help is here--in Anne Strieber's famous diet book "What I Learned From the Fat Years," Anne Strieber shows you how to do just that. And this download has now been reduced from $5 to just $3!