Best Bucky, indeed. And desperate-to-help, horrified-at-his-perceived-incompetence Steve is a very good Steve as well. But he's got no good chance here - he'll learn very quickly not to tease Bucky, to treat him very gently but not like a little kid, not to ask questions he can't answer, all the obvious stuff. But the OP reminds us Bucky's trauma is hidden and unpredictable, because of course it is, after seven decades of globe-spanning Hydra shenanigans. Steve finds the cutest, funniest nature documentary for them to watch, and he's previewed the whole thing to ensure it's predator-free, and Bucky really seems to find it relaxing and charming until he's in a full-on panic attack because the opening narration mentioned these river otters live in Brazil and one of his most fucked-up missions/punishments was in Rio. If he could have said something, he would have just said "let's watch the snow monkeys instead" but of course he can't.