Superstition ain't the way!

Human beings are scared creatures, even though most people mask this or "put on a brave face". Seriously. We're timid, easily worried, and we need consistancy. Many people find such consistancy through superstition - never walk under a ladder, don't let the groom see the bride before their wedding, etc. But we don't know why exactly we do or avoid these things, except that they're "bad luck". They're common sense, and we don't even know why we do them!
Most superstitsions date back to hundreds of years ago - which is probably why some seem so odd. There are many that are passed on as truth, but are not given a reason - they're just simply (not) to be done.
Weddings have a ridiculous amount of superstition attached. Some that you may not have heard of are the ones regarding the date - did you know that if you get married in May, your marriage is supposedly doomed? Why? Because, in Roman times, May was a month kept for making offerings to the dead. And nobody likes a dead marriage. June is the best month, as it is named after Juno - the goddess of marriage, not the quick-witted pregnant teen (although it is worth noting how she got pregnant out of wedlock, but she is named after the goddess of marriage. Diablo Cody is a clever cookie, no?).
Friday the 13th is obviously an unlucky day for anything, not just marriages. But why? Yes, the number 13 and the day Friday are both considered unlucky. But why is that? It seems many people suffer from paraskevidekatriaphobia (a fear of Friday the 13th), and have no idea why. Friday's superstision of bad luck dates back to when Christianity was everything. Anyone remember a certain fellow named Jesus who died on a certain Friday? There are many old texts that refer to bad things happening on Fridays, too. The number 13 also relates back to religion. Jesus' traitor, Judas, was said to be the 13th person to sit at the Last Supper table - and surely anyone who assists in the killing of the supposed Messiah, then later kills himself, is not very lucky.
So, it started with people refusing to be the 13th person to sit at a table, and later it would escalate to more general tasks regarding the number 13.
Another common superstition is that you shouldn't go swimming less than an hour after eating. Let's think about this reasonably - why would people think this? A common reason could include cramps, which could lead to drowning (actually it can't cause cramps so bad that you won't be able to keep afloat, but this isn't Myth Busters).
There is one particularly interesting superstition that if the first person you walk past on the street is a virgin, you will have bad luck for the day, but if they're a prostitute, then you'll have good luck. Uh, yeah. Maybe if you've got money and about an hour to spare.
Chain letters (or emails, nowadays) are particularly interesting. They usually involve one or more of the following ideas: promises of wealth and/or fortune, threat most likely of supernatural variety, or a sympathy forward.
There are also "funny emails" that people are asked to forward, but these do not contain all the elements of the others.
The fact is, nobody (or hardly anyone) is so vulnerable that they believe that forwarding an email will grant them good luck for so-and-so many years, will make them millions of dollars richer, will cause them to die a horrible death, or will enable a little girl in whatever third world country to have whatever expensive life-saving operation (or, for you nerds, Hotmail to not shut down). It's just common sense. Yet, these emails and letters have been circulating for years. And the reason why is that in the back of everyone's mind, it triggers a little inckling that it might be true - just like what their mothers told them about bread crusts and curly hair.
A horse shoe is not going to give you good luck. You will not have a horrible marriage if you are wed whilst wearing anything green. A murderous mental institution escapee with no eyes will not eat your internal organs if you don't forward that chain letter/email. And carrots don't even slightly improve your vision (unless you eat carrots and carrots only for the rest of your life). But we all know this already. We just keep acting on superstitions because they make us feel safe, and hoping that the black cat we passed yesterday wasn't an omen for any dire situations in the future...