Think about this for a moment: when introducing yourself to unknown people (outside of work, so imagine a date - or dating website -, first lesson of a language course, a party, anything social really), what do you talk about? Place you live, work you do, hobby's you have?
My theory is that about 9 out of 10 people will talk about work. And if you don't start talking about it yourself, the other person will ask you about this - most likely in one of the first questions.
Why is this? Why is the work we do such an integral part of our identity in this society?
The type of work you do clearly is a way of cutting out your place in this world. And for the other person, it is a way of deciding where on the social ladder to put the person you are talking to. And the more I think about it, and the more I'm in situations that this is happening in, it is starting to annoy me more and more.
Work is an easy identifier: everyone works or is trying to get work. So in a way it is a 'safe' topic as everyone can relate. Talking about other interests that you may have outside of work are most likely more difficult as a conversation opener: chances are that the person you are talking to doesn't have that same interest and it will take longer to find a mutual topic to talk about. But isn't half the fun talking and finding that mutual interest? And aren't those other topics so much more interesting to talk about and get to know the other person?