co-worker: "Hey, James. What's a plate boundary?"
me: "You're talking about geology?"
co-worker: "Yeah. What's a geologic plate boundary?"
*fifteen minutes later*
me: "...and so the theory, as I understand it, really reaches way way back some 4.5 billion years to what's called the Giant Impact: the supposed collision between Earth and a roughly Mars-sized body called Theia, which was in Trojan orbit at a Lagrange point... I think. Now, Theia no longer exists. But, this collision is believed to have created the moon, and ejected out into space most of the materials that should've formed our planet's continental crust. Thus, Earth doesn't have enough continental crust to cover its surface, and so even now, we have active tectonics driven largely by magma rising and puncturing relatively thin oceanic crust..."
co-worker: "I want to die now."