While in public schools the language teaching system is usually quite bad (all Hologirls had English in school and the only thing they can use is some basic vocabulary - but with proper tutoring and practice they can make great progress I'm sure), specialized language schools (and good tutors) implement more varied methods, which will make you read, listen to and converse in the target language. I remember attending English courses 30+ ago, when schools in my country were changing from Russian to English, and it was like you said. Last year I signed up to a local language school to get my German up from Dummkopf to conversational level and there were games, quizzes, at least 1/3 of the course was conversation between participants, under the guidance of the teacher. They do the same for English courses and they also have English classes for little children, with songs and the like - my point is that a lot of language teaching programs are bad, but there are also excellent ones that will actually teach you something. You only need to find them, pay for them and be dedicated enough to participate.
Regarding the mastery of the language - for most people it will take years to get all the nuances and intricacies right. Every language is easy and logical until it suddenly stops being like that and you have to start to listen/read/speak yourself and figure stuff out. With how widespread English is, there will be groups using it differenly/incorrectly and that's... normal, as language is a constantly changing thing.