Plaça de Catalunya is the “center” of Barcelona. At least when you arrive at the airport all the signs lead you there, and the aerobus will drop you off at Plaza Catalunya as well. As it is perceived so touristic and hectic, local Barcelona people mostly avoid being there.
El Corte Inglés, the nine floored shopping center located in the middle of Plaza Catalunya, has the same unfortunate reputation as well. But there is a secret place hidden in that building. The roof floor has a café (La Rotonda) where you dominate an amazing mute view of this chaotic beauty.
To start the day with a morning coffee and to remember how beautiful the city is, I think this is your address.