These include, but are not limited to:
military time, living in dorms again/eating in a cafeteria for my meals, not using my American cell phone, paying to do laundry, not using a dryer (most of the time), no wireless internet in my dorm room, taking public transportation everywhere, shampoo/other toiletries costing twice what they do at home, not really eating breakfast, stores being closed for siesta times, marble floors everywhere—not just in nice places, and of course, the obvious language barrier.
And last but not least, finding a balance between schoolwork, traveling, and all of the other miscellaneous things I have to do (laundry, going in the grocery store, keeping in touch with people from home, writing in my journal/this blog, etc.).
I say these things not because I view them in a negative light, but rather for the sake of reflecting upon the differences between cultures/residential situations.
With that said, the hardest/worst thing is definitely not eating breakfast. I look forward to the day when I’ll be able to have my cereal and orange juice every morning again.