In cooking, there are two roads you can take. If you have fresh, local, good products, you should mess with them as little as possible. Let the flavors of the food shine on their own.
If you don’t have fresh, local, seasonal fish, produce or meat, you have to fuss with what you’ve got, use sauces, many ingredients, herbs, cooking techniques, etc to make food taste anything half decent.
Remember how I said Spanish food tends to be atrocious? That’s because they can’t stop fussing around with wonderful products they’ve got.
Example. In Tudela, they have the world famous Ugly Tomato, which is an heirloom tomato that tastes out of this world. We visited this local hole-in-the-wall eatery that serves ugly tomato salad. The tomato is so good that all you need is a pinch of salt and a drizzle of balsamic, and you’ve got a meal. But instead of letting the tomato be, the cook dumped a can of tuna on top of the tomato. Cheap canned tuna! On a fresh heirloom tomato! Why, gods of cooking, why?
Even in San Sebastián, a place where cooking is historically revered, you can find correctly cooked, unmessed with seafood in one very overbooked, very expensive place. Everybody has seafood. But everybody else messes with it. Cans of tuna or old, very salty anchovies dumped on top of everything are ubiquitous. If you’ve got extremely fresh fish like they do, all you need is put it on the grill for 3 minutes on each side and you are done. If you have old, defrosted fish that’s lost all flavor, then of course you need to do sauces and try to build flavor. Canned tuna is still a horrible idea, though.