Windows 8. Why?

Am I the only one who is so confused why Microsoft decided to go with this whole metro style. I find myself almost never using the metro interface. I used to use the start menu to search or access documents and other library's but now I just go straight to the file explorer in my task bar and use start + f to search my pc. Can someone tell me why Microsoft didn't make a proper desktop OS with the standard start menu and just use the mobile OS they already have for tablets instead of this RT shit.