When does speaking a foreign language stop being a party trick?

I imagine I'm not alone in this: learning a foreign language, there's something that makes me so giddy about hearing native speakers use vocabulary or grammar I've learned in conversation. For example, I remember when I learned the Japanese grammar, 〜ておく, which is a verb modifier that adds the meaning of "[such and such] done in preparation [for something]" (e.g., "I printed this out (in preparation)"). Learning that, I thought, "That's some weird grammar and quite specific." I didn't think it'd be used very often.

So you can imagine me being surprised and tickled when I realized that Japanese people use this grammar all the time.

What causes these sort of reactions is that we're learning the language with more mature minds instead of just absorbing it as our brain develops like we did with our native languages--we learn the language from a mechanical and structural standpoint, so there's a strange "behind the scenes" sort of feel when we see the puppeteers tugging strings around.

And, unfortunately, that can really make me feel disconnected from the actual conversation I'm having at a given time. Most recently, it came up with my host parents that there had been a death in my family when I was younger. As I told them the story, which had some pretty heart-wrenching plot points, I realized I was more caught up in structuring the sentences; more so than feeling sad about what happened, I was strangely elated by being able to tell the story. The emotions were so gruesomely converse that I felt a little mangled in the process.

So, I ask you the question: at what point does a language stop being a party trick, a skill you can show off by saying certain phrases or telling your friends how to say certain words? When does it become, above all, a realistic communication device? How do we facilitate that transition?

If you've had experience in the transition, let me know in the comments! Am I alone in this phenomenon?