If you know English well, an incredible amount of
resources becomes accessible: books, courses, videos and of
course, a great part of the Internet.
Most of the blogs and websites are in English (second place is Chinese).
Many positions require dealing with clients, service providers or colleagues from other countries. In those cases, your knowledge of English is a critical advantage. It can help you advance further in your career.
You can speak with confidence and
get your message across clearly, instead of hesitating and stammering.
Even in non English speaking countries, it can be very helpful for a tourist to know English.
You can do that while you travel to a different country or even from home using the Internet!
You can watch movies, read books and listen to music in its original and untranslated form, which is in most cases more authentic. And songs tend to be better when you can truly understand them.
Well, it's a GLOBAL LANGUAGE. As an example, a German person and a Mexican person can communicate using English. They usually wouldn't communicate using Bulgarian...
The bottom line is this: more and more opportunities.
You simply have many more options, and those options can help you in life.
Like in mastering anything, it involves learning, and practicing, and making mistakes, and picking yourself up again. It takes time and money, but most of all, it takes will power.
However, it doesn't have to be backbreaking. Not if you do it right, and step by step.