La Paradeta

La Paradeta was surely my favourite place in Barcelona to eat some fresh seafood. 
When you arrive you can choose what you want to eat directly from the counter, as if you are in a market, and tell the waitress how you want everything cooked. After you've ordered (and payed for everything), they give you the number of your table: as soon as something is ready they call your number from a microphone and you can go pick up what you wanted. Given to variety of seafood (but also the good prices!), the place is usually quite crowded and noisy, but it is really worth to try at least once.