Since you asked for a tale of how Windows 8 is terrible
The jarring mode-shifts and complete uselessness of the interface as sold ( as a mouse and keyboard user ) is a good starting point- if I have to install extra software to make a consumer operating system usable at all, that is not my problem, that is the OS Designers'. But that isn't all.
Originally with 8 it was very hard to shut down your computer- a three step process where it used to be one-step. All of these places where they make it more difficult to do things that every user needs to do on a routine basis, they are failing.
When I want to browse through images in a folder, Windows 8 jumps me to a full-screen ( or tile or whatever it is ) gallery application and after the initial image I have opened it just seems to pick at random from the pictures stored on my machine. It is massively unintuitive and means that this is another function for which I simply don't use Windows any more.
A few months after I set up the machine, I edited a couple of photographs and deleted the originals. For some reason Windows 8 interpreted "delete" to mean "Smear file contents across everything on the hard drive" and proceeded to wipe out half of my music library and cost me weeks of work. Call me old-fashioned but I consider manipulating files to be the primary purpose of an operating system. If it can't do that, then no amount of annoying interface tics is going to win me over.
The desktop search in Windows is very good, enough so that I use it a lot of the time. But in 8 it can be hard to know whether when you're looking for a way to change system configuration you are going to get bounced into a Tile Interface view or something useful.
The Windows Store- they obviously want to drive people there, but they have done a terrible job of making it useful and it is largely full of junk. I wouldn't buy from it, in fact I would go out of my way to avoid buying through it.
Compatibility is surprisingly poor - the other day I used a USB display adapter that caused the system to bluescreen at boot. Not Microsoft's fault, of course, but it all makes the operating system seem bad. If I have a new piece of hardware that doesn't appear to work in Windows, I can boot into Linux on the same machine and test it there. With Mint I find the hardware I add works first time every time, which used to be the case in Windows during previous versions. When the 8.1 update came in my wireless card started randomly dropping connectivity. It's an Intel card on a Windows system, which is about as mainstream as you can get, and they have hundreds of reports of the same problem for the same card. It's still marked on Microsoft and Intel's sites as "Compatible With Windows 8" even though this is self-evidently a lie.
All these things create cognitive friction. In almost all cases, when a user notices your operating system that is a bad thing, and I am constantly being reminded that I am using Windows 8 in a way that hasn't happened with any of the previous versions of Windows I have used.
Also, by way of comparison, I have found Mint to be smooth, easy to use and very reliable. If I had to choose between that and Windows 8.1 when setting up a computer for my mum, I would choose Mint.
I don't have a passionate dislike of Microsoft ( my day job involves using their development tools so I benefit from their work and understand their systems reasonably well ) but I have developed a passionate dislike of W8, even once I got a start-menu replacement installed and curbed it's most irritating excesses. Hopefully 10 will be a little less tiresome.