Oh, mechanical engineering

I'm hoping to study nonlinear vibrations for my PhD work. My dad was telling me about the response this gets when he's talking to his friends about me.

Dad: You've chosen an awkward area of study. I tell people you're studying mechanical engineering, and for most of them, their eyes glaze over. But then there are the people who ask, "What area?" and I have to tell them "Vibrations." And that leads to a lot of jokes.

me: You could always say "Nonlinear systems."

Dad: Hmm. That's an idea. Then everyone's eyes will glaze over.

me: It could be worse. I could be studying lubrication.

(pause)

Dad: If that were the case, and people asked me what area of mechanical engineering you were studying, I think I'd tell them I didn't know.