If someone asks you that based on what criteria a loan can be granted to a bank customer you would probably talk about the customer's past and present financial status. You can even object against the bank manager when other irrelevant hidden criteria have been considered to reject your request, e.g. racism.
But I think we cannot object against an officer who rejects our visa. So, my question is based on what criteria Schengen visas are granted? And I mean real or 'hidden' reasons to grant/refuse visas. In addition, are those criteria available to us to read them so we can object in case that visa is refused?
PS The reason that (I joined to travel SE community and) am asking those questions because my application for home loan is rejected today because my signature is a mathematics formula and has "appeared strange and even offensive" in the bank manager's eyes !! (in Georgia). He also said "is it a code? for like a bomb?" !! My passport is Iranian and the countries are usually intend refusing to give visa, so it may be happily an excuse for them not to grant me a Schengen visa.