for one a superstition is saying this thing is making it happen
where as opposed to going to the kosel for instance you want Hashem to listen to your tefillos and the best place to do it is at the kosel b/c Hashem has more rachamim for people that daven there. Im guessing the 40 days is b/c moshe rabbeinu davened for 40 days and was answered
this is my humble opinion