There wasn't anything I didn't find difficult or unexpected, although if you are like me, the group hiring fair can be a little intimidating and awkward. The big tests thing, and they tell you this, is to be yourself. I would add, that even if you are uncomfortable, still smile and try to have fun. You might surprise yourself with how much you already know about the products etc. during my one on one interview, I found the most difficult question to be " what do I aspire to be?" It seems a bit of a loaded question, but answer honestly.