Fellow blogger Crys has a good series on cultural differences, particularly between Italy and other countries. Something I like to think about are cultural differences between atheist groups and queer groups.
Back when I was an undergraduate, I joined both atheist and queer student groups. The most obvious difference between the two was that the queer groups were very quiet, and the atheist group was very loud. Queer groups would often have awkward moments of silence, where everyone was hoping someone else will choose to speak. The atheist group was full of interruptions, even when we’d try to impose moderation.