Some people seem to believe that you can work anywhere if you only speak English.
In Amsterdam it's not a huge problem if you don't speak Dutch.
English can take you far, at least in the city centre.
In the rest of the country, it's different.
In Germany, English is usually not enough.
How is the situation in your country?
Of course it's a problem in most non-English-speaking countries. How can you possibly make serious friends with whom you share your heart and talk about deep things if you can't communicate?
Many countries have only a limited number of fluent or high-level English speakers.
Some people choose to never learn the language of the country, and they just hang around with other people who speak their (foreign) language. This is not integration, it is isolation. And it is not isolating only for the person who won't learn the local language, it is isolating also for the locals who feel this wall of impossible communication with this person.
Even here in Canada we have many immigrants who even after many years have not bothered to learn English, and it is so hard to make friends with them because no matter how hard you try you cannot communicate. I have had a few failed attempts at befriending such people. And they don't desire to learn, so you can't even help them.
The same is the case of an English speaker going to a non-English speaking country and not learning the language of the people. They isolate themselves from the locals and remain a foreigner in the eyes of the people, as they cannot communicate. Really sad!