"You don't strike me as a man who misses very often," Bucky replies, casually.

But then, he is just that, isn't he? A man, and a fallible one at that. Doubt can be as dangerous as it can be helpful, and in this instance, it's the latter, at least as far as Bucky is concerned. Suddenly, Bruce seems like less of an idea and more like a thing made of flesh and blood.