I agree that it really does depend on the subject and the person. Doing an AQA ICT exam with no revision at all was the easiest thing I have ever done. In a generation in which technology is massive, anyone with common sense could answer the majority. Writing about the advantages and disadvantages of social websites and entertainment technology for 12 marks? Anyone could do it.
As well as this, in my opinion but not everyone's, I found both English Language and Literature pretty easy as they don't require much knowledge, only analytical skills.
On the other hand, I have to try a bit harder for subjects such as Maths and Science, merely because I'm not as confident with them. Whereas other people achieve great grades with minimal effort. GCSEs are not easy, as many have said, this can't be the case as regardless of the amount of revision done, not everyone achieves A*s. My friend put in about 10 hours of work for History and ended up with a B, I did last minute revision and came out with an A*. It depends on natural ability for some, and dedication for others. GCSEs are not as easy as people make out.