Ad-slinging on paid platforms
Ads bother me if they pop-up, block pages, interfere with my browsing experience, etc., but what really burns me is forcing me to watch an ad on a platform that I have paid for. If MS can't make enough money without ads in the OS, then charge a bit more for the product. Otherwise, show me ads but give me Windows products for free.
This is the same beef that I have long held with cable companies showing me ads in the same fashion as free1 OTA television.
1In CA there are no TV licencing fees, you just need an antenna.