I've been in similar situations at times in my life, and was similarly frustrated. I didn't react well, during those times, because I was really dumb.

What I would ask my formal self, if I were faced with him, is: have you tried telling the truth? It's weird to imagine, but my logic at the time is that I was being invited into an interaction that I had no interest in ("What are your plans for the future") and because I didn't want to be in that interaction, I responded un-gracefully.

But there's another kind of conversation I think could have been on offer, and that would have been kind of interesting, which is to literally say some of the things that you have just said, or that I was thinking about back then, and see what came back. At least then I would be having an actual encounter! And older-me has found that those can be strangely interesting, and sometimes really lovely.

Like, you can walk away feeling really connected to someone when you say something like: The thought of getting a job and going to it for the next couple years -- let alone for the rest of my life -- makes me want to vomit, or kill myself. That is the introduction to a real conversation, real connection. You can't say where it will go, but at least it's something. It's not just tepid pro-forma bullshit.

I basically never opened myself up to such things, growing up. I try to do it now, but as you said, this kind of engagement does require energy, there's no getting around it. And I don't always have the energy.

Anyway, that's what I would say to younger-me, maybe it can be the seed of something for you.