There’s lots of annoying things with W10 but the biggest source of grief is fighting the system. You need to spin your mind into the view that there will be updates that I have to install so I how can I manage this so the updating fits in with my plans.
There’s loads of unwarranted UI changes just for changes sake but alternate window managers fix that. Hell I have a venerable W7 system here set to look like Win2k, 'coz that’s how I like Windows to look. I do have a tiny W10 tablet that works suprisingly well for a slow CPU and 2GB of RAM. I use it for browsing, email, control of a few servers and rendering my maps when on holiday. Whilst I have Classic Shell running on all the W7/W8 and WinServer machines I use, W10 shell seems OK that I’ve not bothered.
The biggest issue for many is it looks different. And if anyone mentions the telemetry, I’ll come round and shove those packets where the sun don’t shine. The telemetry coming from your phone that you willingly carry everhwere whilst keeping your Farcebork state updated is much, much worse.