[kk_cz]

maximized window ≠ full screen

in Maximized state the window is set to maximal available size (so you are not wasting any part of the screen) while you are still provided with fast and easy access to relevant OS UI elements

in full screen you explicitly tell the system that you don't want to be distracted by OS UI elemtents (typically in situation when you know that you won't need them for extended period of time, or if you REALLY need every single pixel of the screen)

[sysbell]

I feel your pain. I was using BetterTouchTool to remap the default behavior of that green +, but eventually decided it was silly to use an add-on for something I should be able to change via `defaults`, so I just trained myself to hit Option when I wanted to maximize.

[dnhz]

It's also possible to double click anywhere on the top bar of a window to "maximize."