I think some of the superstitional reasons were given only cause things couldn't be explained !for example animals can sense earthquakes sooner than us people for some biological reasons ,but people used to believe that they possess some sort of super natural sixth sense !
The reason is clear !
Sometimes after doing some works, something happens that peaple think it's cuz of doing that work .
For example , they see a black cat , & after that something bad happens , so they think every time that they C this cat, Something bad MUST happen .
Ok?
I don't know if you believe in optimism ,positive energy & all those stuff .,but I guess that's how superstition works....I mean that It's all due to either chance or inculation that our assumptions come true....so the best thing to do is to get rid of negative ones and keep the positive ones...but if you are too stick to positive ones too,you should know how they work and there is nothing supernatural involved !
The "touch wood " expression has another story behind in deed.In ancient times,people used to wear crosses made of wood and to expulse the Devil they touched the worn crucifixes as a sign of God & Jesus Christ...gradually people touched any wood around as a symbol for the crosses because wearing those became less popular....So ''touch wood' is too get rid of the evil and Devil by the help of God just the same as " اعوذ بالله "
here is another one :im not very superstitious but it usually comes true that when the numbers become Symmetry
it means that someone is remember you for example 12:21
sounds silly?
but it really became true for me
times and times