I studied optics (more specifically, nanophotonics) in grad school. Since then, I've learned a great deal more about actual classical optics while working at Magic Leap. Optics is simultaneously fascinating and frustrating to me. Fascinating because it is so accessible and pervasive in our lives, and ties physics and math together, and is computationally tractible while still remaining challenging for many surprisingly common situations. Optics is frustrating because a measurement error of +/-5% is considered very good, and lenses are complete shit at imaging unless you use a whole bunch of them.