Like most touristy places, the big cities in Spain do a good job of showing tourists what they come to see: sunshine, siestas, palm trees, flamenco dancing, outdoor cafes that serve sangria all day, etc. This is our perception of Spain, but like all places, so much remains hidden--unheard, unknown, unseen.
I'm fortunate enough to live in the Centro, where you'll find all the touristy places, but I teach an English class in a marginal neighborhood called Polígono Sur, which is the poorest area of Sevilla. Here you won't find any outdoor cafes or souvenir shops selling keychains and postcards. You won't see very many people on the streets, except for maybe a few kids playing soccer.
Then of course there's the economic crisis. It's possible that, as a tourist, you might run into a protest, but it's hard to get a sense of why people are protesting unless you're in a place for a long period of time. That's why it's always a good idea to do some research into a country before you go. More than a guidebook, I mean. Catch up on current events, because if we don't, we'll just fuel that stereotype we all hate so much: the stereotype of the "ignorant American who thinks the universe revolves around the U.S.A." When we travel, we are representatives of our country, whether we like it or not, which is why it's important to leave a good impression by being knowledgeable and showing respect.