Over the years, I have grown to really dislike Windows as an operating system to a point where I've removed it entirely from my hard drive.
The biggest problem I have with Windows... is the bloatware. Does anyone even use Cortana? the AI that just sits doing nothing, eating your RAM. There's also advertisements on the start menu that likes to put a bit of stress on your GPU.
Secondly, the updates that don't ask for permission. During my university days; I was working on my dissertation making big progress to the word count in the library. I went to the toilet and came back to a nice blue screen on my laptop saying "Windows is working on updates. Don't turn off your computer" . I had lost all of my progress, and as a bonus - Windows had reinstalled all of the bloatware I had removed before.
Thirdly, the malware, the spyware, the bitcoin miners, the keyloggers and the ransomware. Now there's a reason cybercriminals target Windows operating systems... because they are easy to exploit, and Windows is the most used OS in the world. It is unbelievable how easy it is to bypass AntiVirus software with a bit of encryption.
Lastly, it is overpriced. Especially considering everything above.
Right now, I use Linux and only that. I use it on my personal laptop, computer and my personal server which I use to host my websites and cloud service. I do not get bloatware eating my CPU and RAM, or updates without permission. Malware finds it very difficult to attack Linux since it needs root access, and root access isn't easy to get without good social engineering. I find developing software and websites so much easier since Linux provides an amazing development environment. Last but not least it's free and always will be.
In the past; I never understood why people don't just switch to Linux - but now it's quite obvious. It is in human nature to be scared of change. Windows is what people have been using since 1995 and Linux just doesn't fit into their comfort zone. Also, gaming can be a big pain with Linux since most game developers target the most popular platforms.
To finish the rant... recently, I've been seeing some massive changes to compatibility issues with Linux. Unity3D is now available for Linux! I can now make progress on one of my personal projects without having to switch computers.