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I don't believe in superstitions and think that winning and losing, even in sports betting, really depends on random stuff. People in a lot of countries notice that things often don't go the way we want or predict, so they even came up with names for these situations—Murphy's Law, Finagle's Law, the Law of Meanness, and so on. I don't think it's worth taking this seriously and believing that some people are more favored by fortune than others, or that some people are just unlucky in life. Sports betting is a game of chance with a certain advantage for the bookmaker, so you should be prepared to lose more often than you win, except perhaps for professional bettors.
I don't know for sure why some gamblers believe in superstition when they want to gamble. They seem really bad from the way they gamble - no analysis or even some research. If someone gambles based on superstition - then sooner or later they will lose all their money because they lose and really superstition in gambling is a proof that the gambler is not confident and his ability.
Worse still if they believe in superstitions for sports betting - that's really bad for a gambler to do. Without superstitions - I think a gambler can still win, luck will come to those who keep trying.