For me the most infuriating thing is that Apple completely hides what is actually going on from the user.
Want to manually scale your display to an exact resolution? Go to Displays, Hold down the option key and then click on the text next to a radio button. WTF!!! Who designed this, this is completely non nondiscoverable.
An exFAT external hard drive wasn't "shut down correctly" ... no problem Mac OS will just run fsck in the background and refuse mount the drive or let you examine the disk in Disk Utility until it is complete. If you kill -9 the fsck, you get stuck in some limbo state where you can't mount the disk or run diagnostics on it.
The worst thing I have discovered is Pages... The stylesheets and layout logic make absolutely no sense, it is way worse than Word or Libreoffice.
However the OS does run smoother on a day to day basis than my work provided MacBook Pro 2019 running Mojave, and there is absolutely no screen tearing.