Yeeeah, it happens, quite a bit. It used to happen more when I just got out of high school (where no one bothered with small talk - at least the people I stuck close to anyways? Or if they did, and I gave a honest and complete answer, it didn't feel awkward and they didn't look at me funny) and didn't fully grasp the concept that people ask "what's up/how've you been?", they don't actually want a paragraph of what's actually happening (which I find silly. Why waste breath on a question when you don't actually want an answer worthwhile listening to?).
Apparently a relatively usual answer is "Not much. You?" or "Pretty good. You?" or.. other stuff. And then they reply in the same fashion. At which point, it's usually (unfortunately) my turn to talk again, and, not being capable of pulling random (interesting) things out of my mind, the typical awkward silence ensues while someone tries to find something to say.
Just what do people usually say after the "I'm pretending to be concerned about you, but I don't care about your answer anyways." inquiry? o.O
(Of course, if people actually gave paragraph long responses to the question, there might be more to talk about, at least pertaining to said paragraph long response. So why doesn't anyone do that? Because it sounds like you're self-centered? Or because It's Just Not Done™?)
Ah, there's a delightful answer choice to the small-talk question: "Suicidal." :: snickers::