Why is Ubuntu hard to use?

Hello,
I always wanted from Ubuntu to be the OS which is easiest to use. (For everyone) But unfortunately it's not. And in every update, I hope things to be fixed and they are not.
So I wanted this post to be the post that everyone writes the things that's hard to use. SO maybe slowly developers try to change things.

I'm starting;

- Minimize on click when you click an app on Ubuntu Dock.
(It's easy to do with <gsettings set org.gnome.shell.extensions.dash-to-dock click-action 'minimize'> this command but why is it not default? )
- Pdf viewer app with tabs (like qpdfview)
- Default paint app at least to crop/write text on image etc. (like Kolourpaint)
- A media player with many features (like vlc player)
- Making it easy to change grub's default os / viewing time with default app
- Fixing some update errors to at least make it easy to fix with instruction etc. (For example errors like -> Failed to download repository information, E: Failed to Fetch, Package thunar is not available, but is referred to by another package, this may mean that the package is missing or has been obsoleted, N: Updating from such a repository can't be done securely, and is therefore disabled by default. )