Italian pasta sauces are not one tradition but twenty — each of Italy's regions has distinct sauce families built on local ingredients and technique. The north uses butter, cream, and egg (carbonara from Lazio, Alfredo from Rome, ragù bolognese from Emilia-Romagna). The south uses olive oil, tomato, garlic, and chilli (aglio e olio from Naples, puttanesca from Campania, Norma from Sicily). Understanding which sauce belongs to which region and WHY — based on available ingredients, climate, and agricultural tradition — is what separates competent Italian cooking from generic 'Italian-style' food.
Ragù bolognese: soffritto of onion, carrot, celery cooked 20 minutes, then meat (a mix of beef and pork), white wine, a small amount of tomato, milk, and stock. Simmers 3-4 hours. It is NOT a tomato sauce with meat — it's a meat sauce with a touch of tomato. The milk tenderises the meat and rounds the acidity. Carbonara: guanciale (not bacon or pancetta) rendered slowly, egg yolks and whole eggs mixed with Pecorino Romano (not Parmesan), combined off heat using the pasta's residual warmth. Pesto Genovese: basil, pine nuts, garlic, Parmigiano and Pecorino, olive oil — pounded in a marble mortar, never blended at high speed (heat from the motor turns basil dark and bitter).
The four pastas of Rome: carbonara (guanciale, egg, Pecorino), cacio e pepe (Pecorino, black pepper), amatriciana (guanciale, tomato, Pecorino), gricia (guanciale, Pecorino — essentially carbonara without egg). Master these four and you understand the entire Roman pasta tradition. For ragù bolognese: the Accademia Italiana della Cucina registered the official recipe in 1982 — it specifies a heavy-bottomed pot, no garlic, and simmering at least 2 hours.
Adding cream to carbonara — it doesn't exist in the dish. Using Parmesan instead of Pecorino Romano. Using bacon instead of guanciale. Adding garlic to bolognese — it's not traditional. Cooking pesto — it goes on pasta raw. Using a blender for pesto — the friction generates heat. Treating 'Italian seasoning' as a real thing — no Italian cook uses it. Cooking any pasta sauce separately and pouring it over drained pasta — the pasta finishes IN the sauce.