Why is English so hard?

It depends on your first (native / L1) language:

Pick the first language (that you learned as a child)
to find out how that affects how you learn English? 

In each report: 

(1) Read how each language compares with English

(2) Test yourself on the differences

(3) Take a lesson to learn more about the differences

(4) Learn about specific false friends in English

(5) See what you should learn in each level of English