Lately, I've been frustrated by this question. I actually love my job and love talking about to people about it (check out www.Capterra.com). However, when this question precedes nearly everything else in the conversation, it can seem like an interview question. I know I'm not alone in thinking that "what do you do?" can roughly be rephrased as, "can your job help me in some way?" or "is what you do cool enough for my attention?"
There are those who are genuinely interested in how you chose to spend a third of your day, but more often than not I sense that "what do you do" is more about who is asking than who is answering. I recently spent a week in Chicago, meeting a bunch of new people at several parties. Only twice (I counted) was I asked about my job. It was extremely refreshing to make new friends and not discuss or care about what we do for work.
Even when you have a job you love, there are many other ways to define yourself. This philosophy goes back to my post a few days ago about doing things that make you smile outside of a paycheck. Surely there's a lot more to you and your friends than what they do, so try ignoring that question next time you meet someone - I bet you'll have a much more interesting conversation.
