Like in Windows 8, you had to place your mouse on the far right of the screen to access certain features. Fine with a small laptop touch screen, but clearly they haven’t tried it on a 4k, 42” non touch screen at native resolution where the side of the screen is far far away in term of mouse travel.
I believe to this day, the Windows 10 start menu search feature is non deterministic (I removed Cortana and web search). I can search twice the same words and I won’t see the same results, seems random. You can search “SQL management Studio” and “SQL server management studio” won’t show up at any point of the typing (it did in Win7). It feels just broken.
Having two control panels with some settings in one, some others in the other, and because they progressively move them you are never sure where to find them is just bad.
I have many other examples like that. They are not a matter of taste, it is just bad QA and bad design.