Physics
The deeper I dig into physics (yay, another amateur physicist) the more I think that physics should be taught starting out with quantum theory and move upward to Newton, as it is in nature, rather than from Newton to quantum theory as it was discovered. Or perhaps start with Newtonian mechanics and then take the deep dive to explain Newton. Right now I'm finding it easier to understand Bohr's orbitals model by knowing the electron spin and so forth that lie beneath than to simply memorize Bohr. It may be that I don't understand enough to understand how little I understand. Or I'm just weird. -JRS