Crushed tomatoes and tomato sauce are cousins, not identical twins. They come from the same family but have very different personalities. Think of crushed tomatoes as the chunky, rustic relative who shows up to the barbecue with a loud laugh. Tomato sauce is the smooth, polite one who blends in at fancy dinner parties.
Crushed tomatoes are exactly what they sound like: whole tomatoes that have been crushed into a thick, textured pulp. You can still see little bits of tomato skin or seeds swimming in there. Tomato sauce, on the other hand, has been cooked down and pureed until it’s silky smooth. It’s like the difference between a chunky salsa and a smooth tomato soup.