Cultural Differences

I apologize for my frequent references to my experiences in Sweden. I refer to them because they are relevant to particular experiences I am currently having. They also give me a frame of reference when I am baffled by something in this strange and exotic land.
When we moved to Sweden, things were a bit deceptive there. For the most part, Swedish culture felt similar to American culture. People wore the same kind of clothing. You could catch American television with Swedish subtitles any night of the week. Likewise, American music and fast food could be found easily. Swedes speak English with an astonishing amount of fluency.
All of these similarities really tricked me into thinking that our cultures were almost identical. Now I see that it was a naive judgment. As my stay in Sweden progressed, I began to realize the subtleties (and I'm sure I'm still on the outside) and complexities of Swedish culture. No matter how similar the U.S. and Sweden are, there are significant differences, which, if you really want to learn to enjoy the country fully, you must learn so that you can navigate through without too many embarrassing collisions.
Now living in KSA, it is easy to assume that the U.S. and Saudi Arabia are so different culturally that we have no commonalities. After all, one only need walk around a mall to realize you are a in very different place--despite the designer and luxury stores. Seeing women stroll around in black abayas, heads covered, and faces veiled, is a pretty stark reminder that culturally, the U.S. is light years away from this place.
In trying to understand these differences, and also, hopefully, to discover commonalities, I've been studying a couple of books, that hopefully, are accurate. Understanding Arabas: A Guide for Modern Times, 4th Edition by Margaret K. Nydell, looks at the Arab people as a whole, giving general information about cultural customs and, to some extent, insights into religious practices and how they relate to daily living. The Essential Guide to Customs and Culture for Saudi Arabia, is a more country-specific guide. I think it is especially interesting for the business man or woman as it gives really direct advice and insight. (Again, I hope this is a credible source.)
So far, both books have been helpful. My husbands works closely with many Saudis. My husband and I have been discussing the things I'm learning and have found many specific instances where it has been useful.
Sadly, my interaction with Saudis is limited. I'm observing as much as I can, venturing to speak when I think appropriate, and studying all available material. We have been invited to stay with two different Saudi families in Jeddah--invitations we intend on accepting as it provides a rare opportunity to get a better understanding of this really different culture.
In the meantime, I continue to observe as intently as I can. At this stage of the game, I want to learn more and get a better understanding for the reasons behind various cultural aspects that I observe. I promise to share my insights.
What do you know about Saudi Arabia? What aspects of their culture do you find perplexing or interesting?