there is even the term Polak-katolik to signify real Polish identity
There was a superb scene in the sitcom "Świat według Kiepskich" when the main character, alcoholic Ferdek Kiepski says to his wife: Halinka, ja jezzdem Polak!, jezzdem katolik!
Another sign of Polish identity is (was?) alcohol. I remember Ferdek Kiepski painting himself black (for reasons I can't remember) and then drinking a lot of vodka. Next he walks out into park staggering heavily where two old and noble and elegantly dressed ladies sitting on a bench see him and one of them cries out with indignation:- Patrzy pani, Murzyn - a pijany jak Polak!