(I don\'t want to hear about how crazy I am to want that! :)
Focus-follows-mouse is also known as point-to-focus, pointer focus, and (in some implementations) sloppy
There is also the related issue of raise-on-click. Under OSX each time a window is clicked, it is also raised, thus potentially hiding other windows. This is problematic when working with copy/paste from two windows where one of them covers most of the screen. I like to keep a global (active in all workspaces) notepad from which I copy/paste stuff (could be anything from commands, text, todo items etc). This is challenging under OSX. It would be nice to have an option to disable raise-on-click.