Garret Keizer's Notebook column on the death of privacy in the current issue of Harper's is well worth a read. Unfortunately it's not online yet, at least for non-subscribers, and I don't think any one passage is relevant enough for me to key it in. But it did resonate with something I've been feeling.
I know this may sound harsh, but when I'm out doing the meet'n'greet thing, it annoys me that everyone's initial query without fail is prying into your professional life. I realize, of course, that my reticence here is tainted by a desire to hide what a miserable failure I've been, but even if I weren't, it's really not any of your damn business what I do unless you're planning to marry me. I suppose it's the easiest way to find a conversation piece, and people think they're clever if they can pepper you with questions about your job, which I admit I've had to fight to hold my tongue in this regard as well.
Besides this, there's also a subtly competitive undercurrent at work in this practice, as if, rather than having an amicable conversation, you're sizing up an opponent for a verbal joust. And, naturally, it serves as a way to reach a quick, haphazard judgment on someone. (This is just to hopefully show that my consternation here is more than my own personal shiftiness.)