Exams are meant to be challenging. That's the whole point of them, to test you on your knowledge.
I don't understand this notion between students, especially present day GCSE ones, that exams are supposed to be easy. Then, after coming out of an exam shocked by its difficulty, they say 'at least the grade boundaries will be lower!!!'... Well everyone must've done badly across the country for the boundaries to be lower, so why would they help your grade in any way if you've done that badly?
If you know your stuff, then they won't be difficult to the point where you have to say 'that was really difficult'. All exams should be fair but also a challenge, to test whether you actually know what you've learned. Why would the government get exam boards to create easy exams? Anybody could do well in them in that case - that defeats the point of an exam.