Back when I was 12 or 13 years old, I made the consious decision to always have a great day on Friday the 13th. I also decided that I would never be concerned about black cats crossing my path or any of the other commonly held superstitions. I don't think bad things come in threes. I don't believe in beginner's luck. I am careful with an umbrella inside the house but only because it's more likely to knock things over rather than because it brings bad luck. The same is true with walking under a ladder. Just be careful, it's not intrinsically unlucky.
One of the biggest superstitions of all, at least for knitters, is the boyfriend's sweater curse. The superstition is that if you knit a sweater for your boyfriend (or girlfriend), you are dooming the realtionship to failure. Now that I think of it, it's probably in the same category as having your significant other's name tatooed on your body. I think having anyone's name tattooed on your body has it's risks but I knitted my husband a sweater the first year we were married and here we are 46 years later and still together.
I must admit that I do knock on wood occationally although I've never had a rabbit's foot. I think finding a four leafed clover would be lucky but only because they are not common and you have to really look for them. I always set my cowboy hat on the crown so the luck won't run out but I don't worry about how a horse shoe is positioned. I guess in the end I'm a tiny bit superstitious but only in little ways.
As far as today goes, it's going to be great! Friday the 13th or not. We pulled fecals on all the livestock yesterday and they are all negative or very low at 1+ which means none of them need to be treated for parasites. We survived the freeze last weekend with flying colors. The temperatures are mild, if somewhat odd for January. Our Roc Day get together was fabulous with lots of friends stopping by. All is right with the world - at least in this little corner of the world.