I love Barcelona. I really do. Hey, just a couple of days ago it was Corpus Christi, and they have a cool local tradition: on Corpus, in the fountains in the city's several medieval cloisters, they place an egg on top of the spout and the water plays with it; I assume the inside of the egg is blown out first. Anyway, though, the egg is continuously held aloft by the water spouting up. It's called "l'ou com balla"--"the dancing egg". It's pretty to see inside the cloisters at Santa Anna or Felip Neri or Sant Pau.
But I bloody well hate the verbena de San Juan, St. John's Eve. San Juan is a big holiday in Catalonia and they blow off tons of fireworks and everybody goes out and parties their asses off. There is an excellent fireworks display every year, but my problem is that every single kid in Catalonia is blowing off hundreds of firecrackers per second even as I speak.
I don't like big crowds or loud noises. They make me nervous. They frighten the cats. And I don't like party nights when everybody goes out and gets wasted en masse. It's amateur night, a whole lot of people who aren't used to drinking hitting it way too hard and getting smashed and puking all over the place and starting fights and generally acting like a bunch of morons.
Conclusion: If you like going out and wandering the streets and getting trashed and spending lots of money and being subjected to sharp loud noises and getting puked on, San Juan is your night. I will admit that the city's fireworks display is pretty spectacular for people who like that sort of thing. But except for that, I stay home on the night of San Juan.