One morning around the graduate college dining hall, there was a gathering of physicists, finance students, and economists. The physicists are always quite amazed by those people who decide to forgo the life of the ivory tower, and choose to strike out into the real world, and so could not be kept from asking what the economists actually did. Furthermore, we could not be kept from wondering aloud what type of mathematical models they built and polished, and whether any of them had a physical interpretation.
One of the economists scratched his head, drew a sip of black coffee from his porcelain cup, and mumbled something about how a large proportion of the physics department of Harvard University was hired by a trading company, with the lure of riches beyond the pale of the meager imaginings of the physicists (“you mean I can afford a house?!”).