Windows used to be software you bought, and could use with a decent amount of control (obviously not at the level of linux). Windows 11 is a front-end to advertise Microsoft's cloud services. There are ads for them (and also other ads) throughout the OS, and you can't really easily escape the nudges to use them. It also needlessly removes a variety of customizability that has existed for decades; the taskbar is locked to the bottom of the screen, for example, while you could move it to the left/right/top of the screen on all Windows versions since 95.

Being forced to use 11 at work convinced me to finally move to Linux at home. And for context, I was an early adopter of Vista, and remain a defender of it.