Tomato sauce is sour as is mozzarella cheese. The crust should also provide bitter notes, particularly if it has a decent char. There are loads of other topping

Tomato sauce is sour as is mozzarella cheese. The crust should also provide bitter notes, particularly if it has a decent char. There are loads of other topping that provide these notes but stronger, with a more congruous flavor profile to pizza; olives, balsamic vinegar, pickled artichokes and peppers, etc.