Religion

Mary is worshipped as a deity despite whatever the official status is.
The religion has never been able to rationalize the status of its alleged monotheism with its claim that there are three instantiations of 'god'.
Many of the early saints are syncretic transfers from greco-roman pagan gods. They are also worshipped individually, again irrespective of the official doctrine regarding what a saint is.
As the religion spread into other cultures its syncretic nature incorporated indigenous religious ceremonies and gods into (generally) catholic festivals and saints. See for example Mexican catholicism.