Grammar is the glue that ties together all words in a sentence in any language. Not knowing grammar can be very frustrating and sometimes even embarrassing, so getting the basics of Russian grammar down is worth your time has more grammar then English or other languages do, but fortunately it's all very structured, and one can learn it if one put in a little effort.
One may be surprised to find out that English and Russian are very distant relatives. Both come from the same antecessor Sanskrit, and both belong to the same family of Indo-European languages. Although they're distantly related, they have one big difference: Unlike English, Russian is a flectional language, which is a fancy way of saying that it has lost of different word endings.
One doesn't need to cross the ocean to immerse oneself in Russian culture; one can find little Russian neighborhoods in many American cities. Whether one wants to enjoy Russian music, or just chat it up with one's Russian friends, one will need to use Russian grammar. The whole point of learning Russian grammar is to actually create Russian-sounding sentences. If one handles this grammatical topic very well, one will be able to speak Russian language as a native speaker.