Superstition is indeed a sign of human weakness. I've heard about a lot of superstitions, and I was amazed at the level of ignorance that is at work in people. The truth is, superstitions are only striving on the ignorance of people who think their destiny can be altered through some kinds of mystical or magical ways. While I partly agree about the existence of the spiritual realm, there are so many things that do not seem right with superstitions. Most of these beliefs are cooked up because there are ignorant people who will buy them.
Many people are victims of superstitions because they lack confidence. To some, it is because of fear, insecurities, and lack of faith. Every now and then, you see people running from things they can't see. Personally, I think whatever that cannot be proved scientifically, anything that doesn't agree with the laws of nature, or anything that negates common sense should not be believed.