Some of the very few reason I have to use windows are firmware/bios updates to systems I use. For my personal use I try to find hardware that I can update the firmware/bios either without an OS or I can do it with Linux (Centos or Ubuntu). However I have ran into some hardware that I had no other choice. In those cases I have to even though I don't want to. At work I have to use Windows because of firm policy, but I hardly ever use it for work most of my work is performed on a Linux box then I find a way to share that info to my Windows box.
I don't like the lack of Privacy and Control on Windows system. Even when you buy Windows you never really feel like you are in control of your system. I hate that feeling. If I have to put up with that on my Android phone or iPhone, I should and won't put up with it from my System Desktop OS. For me using Linux is freedom (Libre) to do what I want to do. Just like in Life freedom is messy, sometimes there are no clean cut answers, sometimes you are all alone, sometimes you just have to roll up your sleeve and figure it out (Though over the years I had to do less and less of it because it just works). I have the freedom to run my own DNS/DHCP server, my own NTP server, my own firewalls, File storage system, I have the freedom to log an analyze my own data, monitor my own network, run my own web-server, and run my own VMs without spending a fortune on server software that only allows me to do very few of the above, or restricts me to certain limits. I rather be Free than be force to use something that restricts me or spies on me.
I use Linux because of principle and I have Learned to be vastly more productive on it than Windows or Mac. I have my Wife, and my Children working on Linux on a day today basis, the only windows box I have is a VM that is hardly ever touched.