When I bought my first slice of pizza in Rome a few days ago, I was in shock at how different the process was compared to America. First of all, most of the pizzerias are very small in the area and are just like counters to order your pizza then take it with you. There is very little seating in most of the pizzerias. When there is more seating, it is more like a restaurant where the prices are a little more expensive to pay for pizza and you won't be getting just a slice. Next, you choose the kind of pizza you want and tell them how big of a piece you want. They cut the piece of pizza with a pair of scissors and then they weigh it to determine how much it will cost.
Usually, the small/medium size will cost between 1.5-3 Euros, which really isn't that bad. This is especially because the slice of pizza is really long so when you ask for it "to go" they cut it in half and stack it like a sandwich for easier transport. <-- Just like in this picture.
Pizza is eaten on the go like this all over Rome. In the United States, when you get a slice of pizza to go it tends to be a triangular slice that is put into a triangular box. This is not the case in Rome and truthfully this way is probably more efficient and saves on a lot of specialty boxes. Also, it's easier to eat it when it's in sandwich form like this rather than trying to eat it as a regular slice or with a fork and knife.
Overall, pizza in America is similar to that of Italy in some cases, but in most pizzerias in Italy there are many differences that can be seen immediately. These are not necessarily bad differences nor are they good differences, depending on your personal taste. It is just a different way of eating, ordering, and enjoying a great dish that most people take for granted in America.