It's the same reason I don't use multiple monitors simultaneously. I feel really productive having full screen apps. But even better is the fact that I have key

It's the same reason I don't use multiple monitors simultaneously. I feel really productive having full screen apps. But even better is the fact that I have keyboard shortcuts set up to switch between apps. It started with XMonad on Linux, where alt+n (where n is 1..9) would take me to a separate workspace, each with it's own apps. Workspace 1 is always my browser, 3 is the terminal, 8 is my editor, etc. I set this up on OSX as well - workspaces are called desktops on OSX and I just set up 9 of them, with command+n being my desktop-switching shortcuts. It works remarkably well, it almost makes me cringe seeing people alt-tab repeatedly, or using the mouse and overlapping windows to try to switch between different apps.