Have you had pizza in Rome? Rome is a good example: Rome has a tradition of thin and crunchy pizza, which is far from the "standard" pizza (which is the Naples one). Rome pizza is pretty common in Rome, tough there are also many places serving Naples pizza. The point is: Italian people living in Rome and going out for a pizza usually distinguish between the two kinds of pizza: for example, I have lived in Rome for some years and, since I don't like Rome pizza ("pizza romana"), I always chose places serving Naples pizza.

In the rest of Italy is the same: you call it "pizza", but you distinguish between places that make good Naples pizza, bad Naples pizza, good not-Naples pizza, bad not-Naples pizza.