If you grew up eating at Italian restaurants in the United States, then of course you'd think that the combination of spaghetti and meatballs is one of the most quintessential Italian pairings there is. In reality, however, this is an "Italian" dish that isn't actually Italian. Italians do eat meatballs (which they call polpette), but they serve a totally different function in the meal.
In Italy, meals have a very specific structure in which pasta and meat are served separately, not together. Sure, some pasta dishes may contain small amounts of cured or finely chopped meat within the sauce, such as in carbonara or amatriciana, but what you will never see in Italy is a large portion of meat sitting on top of pasta.
