Joe is correct about the "acidic taste" but he doesn't mention that spaghetti sauce makers use the cheapest tomatoes they can find which generally speaking have an acidic taste. By choosing different types of tomatoes you can avoid this issue. When I make homemade sauce I use Kumatos. (Spanish tomato variety) Kumatoes are very sweet and do not require any sugar. Another trick is to use a pint of cherry tomatoes in your sauce or try adding some sweet tasting wine.