JUST Mi

I don't understand, why is it so difficult to write a report for Human Resourse Management?
Is it  too difficult to get the report done perfectly?
Why I discovered that I did it wrong after I had already finished it? That made me feel ferstrated. I don't want to write it again. I don't want to take that teacher's class anymore. I hate it all.
Human Resourse Management is hard to study. Human beings are alive. It's hard to understand what people really are thinking like right now or something. So it become a tough question for managers. 
Worst of all, I met a wrong teacher. The contant is fine. But how come I cannot understand what is the main point she wants us to write a report? The relationship between teacher and we students are fine. It is really strange that I cannot do the report perfectly?!  What's the reason and WHY?