I couldn't cope with a lecture theatre full of students. It's bad enough if I get roped into going into a lecture theatre to help a lecturer with something- too many people staring at me :P
I usually get the eye-glazing from non-domestic students when I try to explain something, or otherwise tell them something that they don't want to hear (which is quite often).
The people I work the closest with are either into keeping fish, or thinking about it, so I can get away with talking crap for ages.
I'd like to be able to talk about breeding mechanics of an obscure marine organism - i sucked at biology, and I can't be assed studying again. My academic inclinations are limited on a good day.