TB I always find the hardest thing to adjust to is food. Especially when I moved to Korea. The inability to find the food that you're used to and adjust to food that's wildely different than what you are used to is enough to make you cry and scream.

Clothes can be tough to. At least in qatar you can read on the web about what to wear and what not to wear, but no one tells you that korea is actually quite conservative as well, I was shocked to learn that I couldn't wear spaghetti strap tank tops.

Weather changes are also difficult to adjust to. You can read all you want about +45 temps, but you will never be prepared for it till you actually feel it.

I think no matter how much you read you can never really be prepared for the physical changes.