Very Superstitious..... (NOT!)

Happy Friday the 13th!  It might come as a surprise to most people, but I am NOT superstitious.

Broken mirror?
The only thing I'm worried about it missed shards.

Black cat crossing my path?
Oooooooh!  Look!  It's a KITTY CAT!  Time to pet the kitty!

Walking under a ladder?
Well, there was probably something in the way.

Throw spilled salt over my left shoulder?

Whoops.  You caught me.  I do do that.  But that is more of a habit than anything else.  I picked it up somewhere, lost in the dark recesses of my childhood, and have never stopped.
So today, I decided to find out why people throw salt over their left shoulder, and see why it is considered good luck.

Here is what I discovered:

According to most Judeo-Christian faiths, the Devil, or demons, stand behind your left shoulder.  Guardian Angels stand behind your right.
Salt was a very expensive seasoning and spilling it was considered unlucky.  It was also considered to be connected to all the good forces in the world.  Jesus is referred to as the "salt of the earth", and salt is used to bless and sanctify, because of the lasting and preserving qualities it has.
When combining these two myths, it makes sense to throw salt over your left shoulder.  If you have spilled salt, you have tempted the Devil, so to speak.  By picking up the thrown salt, and throwing it over your left shoulder, you would be throwing salt into the Devil's eye, breaking the control he would have.

The research was incredibly fun to do.  So what are you superstitious about?  And where does the basis of that superstition come from?