It's just a subtle smirk that can make all the difference. And while in America we stress the importance of smiling to strangers and friends to make them feel noticed and importance, it does not contain the same connotation to strangers in Spain. While smiling seems so natural and harmless as an American, it was one major cultural difference that I had to adapt to was smiling.
Apparently in Spain, or at least in the region of Valencia, it is custom to only greet those they know when walking down the street or are in a public environment. My teacher from AIP told me they never smile at a stranger they walk past. The thought had never even crossed her mind to do so, in fact, the concept was so strange for her. She recommended that I not smile otherwise people would think I was a bit too strange.
Easier said then done, it was such a habit I never realized before at how often I smile at strangers. But when I did start paying attention my smiling tendencies, I noticed that it did trigger many strange glances in return. Earlier before this enlightenment, I thought these strange glances back was because they could tell I was a foreigner, which clearly it was, from my height, skin tone, and (now to my knowledge) mannerisms.
But this brought about another major cultural difference I noticed from the Spaniards that is not acceptable in the United States:
staring.
As I further analyzed American's smiling tendencies, I realized most often times we tighten our checks, curve the ends of our mouth up, and maybe so a bit of teeth, to make an expression that is perceived as friendly so that our glances is not perceived as staring.
However, Spaniards do not need to smile because they are not ashamed to stare. They do it all the time and clearly so. On the subway to work, waiting in line, walking past, all sorts of public instances, as uncomfortable to me as it was. Even when I glanced over to make it clear I saw them, their staring persisted; where as if it were an American they would have diverted their eye attention right away. Often times I felt so judged. Was there something on my face? Did I forget to zip up my pants? All these possibilities of reason an American would stare at me popped into my head.
Even though I was uncomfortable at first, I adapted; in the end, I found myself openly staring at others as well and keeping a straight face to strangers I walked past even though our glances met.
Their stares were just as harmful as my mis[non-verbal]communication of smiling.