When Zuzana and Gregorio make tea, they fill a pot with water (normal pot, not a tea pot), heat it up on the stove, then add two or three tea bags to the pot. And can then fill/refill multiple glasses with tea from the pot.
I feel like this seemingly insignificant difference is representative of the larger cultural differences between Spain and the US. Things aren't rushed here. Heck, practically the whole city shuts down from 2-5 every afternoon so that families can return home to leisurely eat lunch together. When eating at a restaurant, you'll need to ask for the bill when you want to leave. They're not going to bring it over when it looks like you're done, subtly hinting it's time to leave; rather, you can stay and chat as long as you'd like.
Sure, people will have places to go, but overall there's a more relaxed feeling here - despite the size of this city.
Just as family is more important than the individual in Spain, the group is also more important when it comes to education. It is very common for university students to lend notes to each other to copy. Sometimes friends will split up days/weeks of class, and each take turns attending and taking notes, then sharing them. Thus, schools are less competitive here as compared to in the US. Students just want to pass, and will help their classmates pass as well. Less competition = less stress.
Perhaps I was looking too deeply into the tea situation. Regardless, I feel as though I've picked up on a few more differences that aren't necessarily above the surface (in terms of the 'culture as an iceberg' metaphor). If interested, I just did a quick search and found this article (Spanish Cultural Commentary) to be a nice, quick read, touching on some things that I did not.
* Belle and Sebastian, of course