My own view on this is a number of the blank responses from passengers is probably because a number of them may not understand the language in which they are being addressed. Although that said, if I board an aircraft in deepest Mongolia I should really have a fair idea of what the FA is saying as I pass through the door......
In my experience over the last few years the CC are surly, unsmiling and generally unwelcoming, almost giving you the feeling that you are bothering them
I fly a couple of hundred sectors per year and I would disagree with that comment. Some airlines are better than others, sometimes they vary in the same airline but generally speaking the CC I come across are friendly, welcoming and helpful. Of course there may only be 4 or 5 of them for approaching 200 people so there is a limit as to what they can do for you on a 90 minute flight.