Just today saw someone I know at a grocery store and had this exchange. I think it's weird to just reply with "fine" or "good", it gives me nothing to grasp. It doesn't need to be an elaborate life story or an essay on your feelings, just something. "oh fine, just getting off from work" and I do the same. Just a small exchange giving at least something. One word replies and just staring back is kinda rude and awkward even more so.