I visited a lot of Spanish cities. Santiago, Oviedo, Gijón, León, Valladolid, Madrid, Girona, Málaga, Sevilla, Cádiz, Cordoba, Granada and Barcelona so far.

As far as the general sense of unease goes, Barcelona takes the first place. Some people there are outright creepy. I generally like the city, but I would not dare venture into the old centre's small alleys after dark.

Also, pickpockets. All touristy places have them, but Barcelona, man...

Shame, because the city is otherwise a jewel.