Visual Complexity of Windows (sharjeel.2scomplement.com)

The thicker border provides a larger area to hit when trying to resize a window.

The only thing I am sure of after reading this article is that I really cant stand the term "User Experience" and the abbreviation "UX".

If you don't like the transparency, turn it off.

This is completely ignoring the fact that windows aren't viewed in isolation. The thick border makes it easy to see where one window ends and another begins.

I find that OS X windows tend to blend into each other a lot more because they lack the border and have much softer shadows.