Why is English difficult?

As I have heard English isn't difficult. The grammar rules of English language are very simple and clear. Nevetheless people spend a lot of  much time to learning it. Why? What is a the problem?

I'm Here are some of my reasons going to describe some of them ( I guess, I will sound my own ones ) :
1. Prepositions.
They are the worst thing in English. There are no one definite rules with them. The number of exeptions are more than the number of rules. The have feature to change the meaning of the verbs fully. It changes the hole meaning of the statments. Using them wrongly changes the entire meaning of the sentence. (Give examples!) Terrible !!!!
2. "Multi-meaning" of the words. Words with multiple meanings.
Almost all Many words have more than 3-4 three meanings. Which of them is used at the moment depends on the context of the conversation. It is very difficult for non-native-speakers to remember all of them and get used right one. The meaning depends on the context.  Very difficult for non native speakers.  (Even so, given the same context, this classic sentence is ambiguous.  "The Queen threw a ball".  This kind of ambuiguity exists in all languages!  Even Russian.  This what makes the language alive. eg "It's a fine city!")

Worse still is that a word can be an adjective, a noun or a verb depending on its placement in the sentence.
The next, the same word can be used as noun, verb, adverb or adjectve concerning if it place in the clause. Terrible !!!

Don't be offended with me. I mean when I use the word "terrible".  I am not for estimating demeaning the language. What I meant is that it is terrible to try to remember all these nuances while listening or speaking.
I mean it is terrible to try remember all these nuanses at the moment of listening or speaking.

And I think Each language has his own "charmings" charms.

Good luck to everyone how studies in learning a foriegn language :):):)

English is not difficult.  It is easy when comparing grammar, neuter forms and less verbial conjugations to other languages.  What is difficult is the horrendous number of exceptions!  I have to remember all these as a kid!