oedipa maas said:
Usually I smile and say "but I think there are a lot of people out there much smarter than me!"
One time I was at a bar during an open mic with some physics friends. After I played my set I was standing at the bar chatting with my pals and a guy came over and complimented my performance. He offered to buy me a beer and I agreed (he was kinda cute and he wasn't inebriated). Anyways, the conversation got around to "what do you study?"... and when I replied the guy responded "oh, you must be smart... umm, I'm going to get back to my table now." So he ran off and left me to pay for the beer he'd ordered for me. I was totally crushed until I turned around and saw my friends laughing hysterically - and then I realized how funny the incident was.

It is funny, but also sad. It's actually easier for me to strike up conversations with people now that I teach classes at the med school. I used to get the same types of reactions when asked what I do...I'd try to weasel around with "I work at the university," first, which is less intimidating. But when they got to what did I do there, and I said I was on faculty, the next question was always, "Oh, what do you teach?" Well, when I didn't do any teaching, I had to explain I only do research, and that led to, "What type of research do you do?" There was NO good answer if the person I was talking to didn't at least have a college education (and I'm the friendly sort who enjoys talking to anyone I encounter when out). I could give very generic answers like physiology, which nobody knows what that means (and yeah, they'd mishear...physics, psychology, physician), or I could answer neuroscience, which got even wider-eyed responses (in their mind, that's close enough to a brain surgeon to be right up in the "it's not rocket science or brain surgery" category of scary smart), and I sure as heck wasn't answering, "reproductive neuroendocrinology." It's tough to gauge your audience when you've just met someone in a bar too, so there's usually this pause as I try to guess the answer that's most likely to avoid scaring them away, but not being so overly simple as to insult them. And, sometimes that's when I just resort to, "breeding sheep," or something ridiculously over-simplified and inaccurate just to not come across arrogant to someone who wouldn't have a clue on the rest of it.
Oddly enough, now that I teach some classes, it's easy. When someone asks, I just tell them I teach at the med school. When they ask what, I just tell them anatomy. They all have heard of that, and for some reason, teaching at the med school doesn't scare people away as much as being a neuroscientist does. I think they assume that makes me a physician and they all have doctors so aren't quite as intimidated (though it does mean I get more of the "My aunt has this mole..." type questions).