I don't see why I am going to waste my time doing this since you seem to not be fond of Apple or it's products. I mean, after all, in the MacBook forum the only thing you could do was insist that it was a netbook over and over again like a broken record. But, I digress...
1.) It feels like two different OS's (an old one and a new one) have been inelegantly smooshed together. It's certainly less of a Frankenstein OS when compared to Windows 8 and 8.1, but it's still really bad.
2.) A weird mishmash of Win32 apps and UWP/WinRT apps that both try to do the same thing. There are two different applications that are dedicated to the modification of system settings, Control Panel (Win32) and Settings (WinRT/UWP) and they both do completely different things and there is little to no overlap. For instance, if you want to change your default web browser you have to remember which one of those apps to open up. Is it in both? Or is it only in one? If so, which one? Control Panel, or is it settings? Okay, now you want to change your mouse cursor to make it black. Where do you have to go to change that? Which app do I do that from? Needless to say, it is clunky, complicated, and inelegant as hell.
3.) There is UI inconsistency galore in Windows 10. Depending on where you right click within the operating system, you might encounter one of around five different context menus. And the font anti-aliasing is seriously weird and not to mention, it is substandard. In Win32 apps you have ClearType 2, and in WinRT apps you have this ugly, gray crap. There are also completely different fonts and font sizes used. Also, apps don't fit together. You can run a modern UWP app like Weather that looks like it is from 2016 alongside Disk Management, which looks like it is from Windows 2000.
4.) The Start "Menu" is an abomination. It is cluttered, horribly designed, and using it results in a very bad experience. It's no wonder that there are many companies who have created Start Menu replacements out there flourishing. Also, Live Tiles are annoying and clutter up the Start Menu.
5.) Bugs. Windows 10 is far more buggy than El Capitan, or even Yosemite, in my experience. If I had a nickel for every time I had to restart my Surface because the Start Menu or Action Center was not responsive and wouldn't respond to clicks or key combos, I would be rich. Action Center also insists on duplicating all of my Notifications for some weird reason. All of these things keep coming up across OS installations.
6.) Depending on what version of Windows 10 you have, there may be no way to stop updates from downloading and installing themselves automatically even if you don't want them to. Even on the Pro version of Windows 10 where you have more control, you still don't have enough control. For instance, you have to install all available updates or none at all. And you know what? You shouldn't have to pay an extra $100 to get slightly more, but definitely not enough control over your updates.
7.) Microsoft is now displaying advertisements on the lock screen of Windows 10. You can turn this off, yes, but the fact that they are even doing this at all is deplorable. Turning users Operating System's into billboards is not ever okay.
8.) There are privacy concerns. You can't turn telemetry off no matter what, and even when you switch off Cortana, the Cortana process is still in the background sending things to Microsoft.
9.) Virtual desktops are nice, but Microsoft has managed to completely mess up how you interact and manage them. At least with respect to using the trackpad, you have to swipe through your windows and not through the virtual desktops themselves. This was a very poor design choice and the way that it works is quite weird.
10.) It took Microsoft about 15 years to add scrolling through inactive windows, but when they did, they couldn't even manage to implement it properly. When I start to scroll through the inactive window, I don't want the inactive window to be made active, and have active window to immediately be pushed into the background, becoming inactive. That kind of defeats the purpose. The feature should not involve any window placement being affected.
And these are just 10 problems that are unique to Windows 10 and not other versions of Windows. I'm sure I could continue this list, but you only asked for 10 and I've already put enough time into it.