Once, eating some pizza in the US, an Italian colleague told me “You see, you should not consider this pizza, but a typically American dish…”. Well, yes, that’s a good strategy. Being a very tolerant and open-mind Italian, I can tell you that American pizza, like American coffee, is not bad, just different. Very different from the Italian version. But different, of course, doesn’t mean bad. But for any Italian la mamma è sempre la mamma (‘mom is always mom’), and la pizza, the real one, è sempre la pizza.
For your Italian friend will be hard to get used to American pizza sizes; Italian pizzerie, and pizza delivery as well, normally serve a “personal pizza”.
Sharing a big pie is not common;
however it happens in a few places that make pizza al metro (‘pizza by the meter’).
The dough is very different: the American one has a different texture, and very often is too sweet for an Italian taste.
Sauce: Americans love sauces, a little to much for the Italian habits; tomato sauce is very thick and seasoned with herbs and spices. In Italy is just plain tomato sauce.
Cheese: Americans use way too much cheese for Italian standars, plus, it is not original mozzarella cheese.
Toppings: this is the hardest part.
Pepperoni in Italian is ‘peppers’, your Italian friends will be confused…
also, many typically American toppings will be quite hard to accept for them. Chicago style pizza… well, it will look like heresy to the most of them.
Once I met a guy from Chicago. He was very disappointed from Midwest pizza. He said: “Pizza here depresses the Hell out of me!” I sarcastically replied: “Oh really?” and he said: “Yes… why? Oh right! You are Italian!”. So in conclusion, my recommendation is: have a pizza party, but make your own pizza! Buy some good ingredients, and you will make your Italian friends happy!