I just had a revelation about why you spend lots of time learning something: to be able to understand something new when it comes your way, or so that's the thought. Who would have ever thought back when I was learning German grammar that there might come a day when I heard "Sie werden gemolken" ("They are milked") in a conversation and understood it.
The conversation was about some cows in a village in the Waldviertel (a place near Vienna) and how they're milked. I've never conjugated the verb "melken" nor have I ever used it passively, at least not in german, so I've never encountered the passsive, present perfect tense of the verb and yet, having learned so much grammar, when I heard it, I was able to figure it out right away. A little pat on the back for me.