OSX is known to have a not so good window manager, in example. Well, instead of improving it, by implementing other WM's standards (look at almost all the Linux WMs and Windows', they have maximize buttons, they stack on the border of the screen, etc) they chose to not be smart and not, oh god not copy what works the best. They chose to "force" fullscreen instead of maximizing, to not implement stacking shortcuts, etc. They are going backwards. And sadly you can say that for a lot of things about OSX