What if I want my taskbar in the middle of the screen instead of the top or bottom?

What if I want textboxes to have flashing orange outlines around them?

What if I want the close button to be blue instead of red?

What if I want the Finder face to be a sad face instead of a smile?

Customizability needs to end at some point. Technical details about font rendering is not important to 99+% of users and is only confusing.