Will you ever fully understand English?
Having studied other languages and understood the expectations I placed on myself (unrealistically), that I should understand everything in another language, I began to think about my own language...English
I lived in the UK for 11 years, and, for example, when I watched TV shows, I did not always understand what they said. There were LOTS of cultural references which were lost to me and many words I could not hear, due to speed, muttering or accent.
What I simply realise now is that I dismiss these instances as irrelevant and un-noteworthy. I would simply enjoy the rest of the show.
It is the same with American shows.
So, I do not think it absolutely necessary necessary to understand every word, phrase or cultural refernce in order to learn a language well.
What are your views?