I've had three very different experiences. First, there was my undergraduate Anthropology Major with a focus on Gender/Sexuality. I think I've blocked out all the conversations on that one but the Anthropology questions were pretty standard. The Gender/Sexuality got weird and into personal business very quickly with a lot of strangers.
My Masters in Library and Information Science was often pretty funny, though.
PersonA: So you're getting your masters! What in?
Me: Library and Information Science!
PersonA: Really!? O_O That sounds so difficult!
Me: ... I'm studying to be a librarian.
PersonA: ...you need a Masters for that?
Through a course on Information Communication Technologies I decided that I wanted to pursue further education on the affect of ICTs globally and locally on communication and culture. Most of the time this actually gets understood--I just point out people's cellphones and the use of Twitter or Facebook (or whatever communication technology they prefer) and the light goes on. Occasionally, however, there's a brick.
Law Student: So you're applying for Doctorate programs in what?
Me: Communication--I want to study Information Communication Tech. Like...the use of cellphones and Facebook and how they change communication blahblah
Law Student: ... and you think you can get a job with that? That's useless.
Me: ... but the more you know about how people use technology to communicate blah
Law Student: Nope. Its useless. It'll be obsolete by the time you turn around.
Me: ... but... you've been using your cellphone to check facebook, comment, and like things since I met you, constantly, for the past 40 minutes. ???
Law Student: If I could use magic to do the same things I would. Does not make a bit of damn difference
Me: /gives up/