My son was invited to a Swiss birthday party. This really doesn't happen all that much to my kids here, in comparison to the international school in Warsaw where usually the entire class was invited. But anyways, in The Netherlands when you go to a party you also congratulate the parents (and grandparents and brothers and sisters and other visitors...), so I immediately started kissing the parents on the cheeks (yes, three times) and said "congratulations!" very cheerfully. Then came an awkward moment and the dad stumbled....."you know it's not my birthday but my son's". Err-mm, yes, I know....whoops!
Also, in Poland when the kids at our birthday parties even smelled candy or cake they would run up to the table putting sweets in their mouths. A little bit like the opening of the birthday presents, quickly and if possible at the door in The Netherlands. The first time we had a birthday party for our daughter in Switzerland, all the girls nicely sat around the table waiting. I thought maybe they didn't like the cake, but in fact they were waiting for my signal to start eating. Wow, that never happened to me before!
So, be aware and don't automatically assume that what you are used to is also a custom in another country.
Robin Pascoe in her book "Raising Global Nomads" (2006) shares her own lessons learned from raising her two children while living abroad, with examples you will definitely recognize and laugh about.
Talking about Culture Shock she explains the different stages: the honeymoon period (everything is interesting and enchanting), the crisis stage (everything is foreign, no longer exotic, although the mom often skips the honeymoon stage having to arrange everything at once), the flight stage (you want to run away and your kids are asking to go home) and readjustment to the new surroundings and having found a new balance your life.
Be aware that Culture Shock is not a single event, but a process in which an individual has to adjust to an unfamiliar surrounding. It is an subjective experience and everyone moving abroad will experience it, although in different ways. Acknowledge it and learn from it while going through the process, on average it will take you and your family one year to adjust. But also keep in mind that sometimes "it's not the place, it's just life that's happening here. Things go wrong no matter where you are."
How do I know I have Third Culture Kids? Because they keep switching between languages without any trouble, my son knows more about geography then the average adult and he even told me that being in the same school for six years must be sooooooooo boring!
If you want to read more about this subject I can recommend "Third Culture Kids. Growing Up Among Worlds" by David C. Pollock and Ruth E. van Reken. And see the website: http://www.tckworld.com/