I actually had that yesterday where I was standing quietly in the elevator going to my floor when someone else hopped in, a resident, and we normally just smile and say "Hiya" or something like that, but this time she asked me how I was going but I wasn't in the best of moods, so I said "oh, idk, up and down, what are you meant to say?" And she said 'oh I just say, "so, so".' So, there we have it. It's an international phenomenon where people, it seems, can't stand the silence or awkwardness and so ask you how you're going. That's what I think it is most of the time.