Utter cobblers IMHO and a sign that people have not evolved past the 15th century. I firmly believe that anyone who thinks that their life can be guided by astrological or spiritual forces needs a session or two with a good psychiatrist.
Religion and customs seems to be the root of many superstitions....click here many suprstitions came about due to people being unable to accept self-responsibility for bad outcomes and the need to blame anything or anyone else for any woes that might have befallen them.
Some superstitions are based on loose facts though.
"God Bless You" after sneezing was because sneezing was one of the first symptoms of plague (and some other things) and was a genuine prayer for someone's continued well being.
There can be few who have not heard of the origins of third light unlucky. It is a genuine fact that the flare of the match drew the sniper's attention, second light gave hime a chance to steady and aim, and it was the third guy that got it.
On the other hand, seven years' bad luck for a broken mirror and spilling the salt must be rooted deep in witchcraft.