Imagine sitting there with imposter syndrome and thinking, "there is so much pressure on this conversation. I need to not only entertain someone much smarter than me, but I have to learn something profound that I can use as an anecdote for the rest of my life." Then looking down at your terrible 1920s German food while he nudges you to say something, but you just KNOW he talks about theoretical physics with everyone all day so he's probably bored of it. Besides you don't want to say something stupid like "Wow E=MC2 huh? That's somethin'. I figured it was MC or maybe MC3 but 2 wow."
But like if you talk about your dog he'll think you're simple so you've GOTTA work spacetime into it and learn something about spacetime so you can tell your grandkids and they won't think you're a loser. Imagine eating bread to calm your nerves and show that you're too busy to speak but then fixating on how much bread you're eating and wondering if Albert frickin' Einstein is judging you for that. And oh boy, now you have to say something EXTRA smart and NOT about theoretical physics to prove that you're not a bread-eating simpleton. Imagine having the opportunity to try to explain what you think spacetime is to Albert Einstein himself while your mouth is half-full of sawdust bread.
That's even worse. I know all the spoilers for socialism. He'll start to say something about how neat it is what Rosa Luxemburg is doing and I'll have to
while choking down my sawdust bread with a glass of river water.
Warn him.