Dorky Poll: Optics or Thermo?

This might be too abstract for a really good Dorky Poll, but I’ve got a bunch of stuff that I really need to do, and I’ve been thinking a bit about curricular issues, so this came to mind:

Which would you rather know more about, Classical Optics or Thermodynamics?

Imagine that you’re being offered a choice by some sort of magical being: you can choose one of these two disciplines, and know absolutely everything there is to know about it, while you will never know more about the other than you do at the moment of the decision. Which would you pick?