A person's image is important. Anyone who thinks otherwise is full of crap. Whether it's because Reddington is just that smooth or because Han just isn't all that familiar with Earth, he his this impression of Ray as sophisticated. That he knows so much about the common drinks around him doesn't suggest to him for a moment that the concierge of crime perhaps drinks too much - it's because he's worldly.

Han ... knows that he can't quite pull off that kind of classy impression for long periods. Maybe long enough to get some doofus to think twice, but not much more than that. He's a bit jealous of people who can make people think they're refined. He wishes he could be.

"The little things ..." the cultural things and small details. "It's always good to know what the right drink to have is."