Of course it's hard, but it's not more difficult than learning other languages.
Also, there's a hugh difference between me learning English and you
learning other languages. Although I live in Sweden, I come across
English almost every day. I listen to English song lyrics on the radio.
I watch American and British films and TV-shows, with Swedish
subtitles. I use English to communicate with people from other
countries on the internet.
For me, English isn't just a "fun thing to learn", or something I study
for the grades at school. I use English in my every day life. That's a
hugh difference!
I've studied English for 11 years, since I was 10 years old. And I'm
still learning and making mistakes. I don't think I'll ever speak it
perfectly. At least not without moving to an English speaking country.
To merely understand English is not a problem anymore. I started
reading books (Harry Potter) in English when I was 14-15 years old.
Writing or speaking English, on the other hand, is much harder and I
wish I could use a more flexible and advanced vocabulary. And less
"Swenglish" expressions (almost litterally translated word by word).
The most difficult part of learning English is probably that English
has so many words (more words than in Swedish). Pronunciation and
spelling is also difficult, because of all the diphthongs and stuff. I
think English grammar is quite simple though. Much more logical than in
most other languages (which doesn't stop me from making mistakes).
But I love the English language. I actually prefer English to Swedish,
since it's a much cooler language. You have many useful words and
expressions which doesn't exist in Swedish.