A simple and fundamental bit: downgrading the OS is a PITA (is it even still possible ?), and dealing with the T2 side of it makes it a million times more complicated.
On more pet peeves level of hostility:
Still haven't found a clean way to get rid of Apple Music. Every single time I accidentally click the play button on my headphones it brings up Apple Music.
2FA verification being bound to Apple devices.
Phasing out kext support under the security reasoning also means decent low level extensions are now a dream of the past. Stuff like Karabiner are notably worse when system perfs degrade, and I'm not holding my breath for linux partition mounting.
I permanently switched to Linux because Windows was acting as the owner of my computer.
The change took some work, but it was well worth it.
Now I'm using Mint with KDE. My regret is not having done this sooner. I'm satisfied.
Ubuntu also displays an advertisement every time I log in:
Get cloud support with Ubuntu Advantage Cloud Guest:
http://www.ubuntu.com/business/services/cloud
* Introducing Expanded Security Maintenance for Applications.
Receive updates to over 25,000 software packages with your
Ubuntu Pro subscription. Free for personal use.
https://ubuntu.com/pro
Expanded Security Maintenance for Applications is not enabled.
While I use Fedora, I believe most frustrated people will look to Apple ecosystem.