>>1
Why do you do it?
Linux is free, open-source, uses less resources than Windows or OS X, and, among other things, has quite a lot of free programs which are nice. It's much more stable and reliable too, and since less than 1% of all people use Linux there aren't many viruses developed for it. And with Gnome's "sudo" it's impossible to have something drastic changed without the user's specific permission. And the reason why Linux-based operating systems are free is because IBM funds developers so the whole "you get what you pay for" thing doesn't apply here.
But aren't there a lot of cool things you can't do without Windows?
No, there are not. If I want to play a game or something I can always just run a virtual machine or emulator to use it. And everything else is good.
If you want to use Windows, OS X, BSD, Solaris, or whatever else, that's fine, as long as you don't try to tell why me the operating system you use is superior to the one I use. Each has their own advantages and disadvantages. Just leave it at that.