I liked this one for its analogy to visiting a foreign culture. I've been to China a few years back, and though the interculture communication made it much less jarring and/or dangerous than it once might have been, there were still plenty of misunderstandings due to my expectations vs. theirs.
If you've ever been to a restaurant in Italy, the difference in culture is very obvious--unless you go somewhere quick like a pizzeria, the service is abhorrently slow by my expectations. In the US, most often you can get your meal even at a slow restaurant withing 45 minutes or so of taking a table, and if you were in a hurry could pay and be gone in a little over an hour. In Italy, the fastest sit down restaurant I went too took at least 3 hours, which was very frustrating for me--I wanted to sightsee, explore the town, not sit inside a restaurant all evening! And asking politely for faster service was just seen as rude, so after a couple restaurant excursions we just started going to the pizzerias where the food was hot and ready and you pre-paid so you could leave when you liked.
Anyway, good story to illustrate the concept of culture shock to someone from any culture.
What I didn't understand though, is what triggered the closing of the big deal. It seemed that he was simply too pushy at first, and when he relaxed and stopped demanding, the alien bought something he didn't need for ridiculously large amounts of money. But in the end, he still didn't need it, so why did he buy it? I guess I'm just not integrated to this culture yet.