Maybe it is indeed because you come from Windows, but OS X doesn't have a Maximize button. The green light of OS X's traffic-light configuration is Zoom. But it's becoming Full Screen in Yosemite, so that should be closer to what you want out of the button.

As to your second point, that probably has the same cause. On OS X, you Cmd-Tab between applications, not between windows. Within an application, you can Cmd-Backtick between windows, but I don't think there's a navigatable collection of all windows across all applications.