Physics education in a nutshell! First day: "Here's Newton's Second Law, F=ma, simple right?" Next week: "So those partial derivatives of velocity with respect to cylindrical coordinates are just the same thing, but for fluids moving in 3D space with pressure gradients and viscosity terms!" The Navier-Stokes equations are basically Newton's Second Law after it went through puberty, got a PhD, and developed an identity crisis. They're mathematically terrifying but fundamentally just describing how force affects motion in fluids. Classic engineering move - take something elegant and make it look like you're summoning a mathematical demon.