It is often worth going to an upper belvedere (here the roof terrace of a hotel in Via Laietana) and see what is around. Buildings can seem rather well behaved from ground level, but roofs, especially when you have flat ones that can be used as in Barcelona, allow a more individual expression (as in cemeteries, you can express yourself through architecture usually with more freedom).
What do barceloneses say from their penthouses? Some have created gardens/forests, some hotels have established their own paradises with swimming pool to enjoy tapas o drinks (not during winter…) and there are many traditional rooftop clotheslines. Those willing (and able) make a statement with towers or domes of any kind.