Here in Argentina we have a lot of superstitos
Personally I believe that when youe left hear is red, someone is talking badly about you and the opposite with the other hear; I know of many times that this happened.
I think you've made a very good question, every place have its own superstitions, I don't know many of the ones here and there are many
I would like to know the ones you know (from your country)
there is the famous number 13, opening an umbrella indoors, walking down a staircase, the black cat (I have one); all of this bring bad luck
if you threat some fruit tree that you will cut it, it will give more fruits
so that's all i can remember now